Water changes, a thing of the past or necessity of the present?

[jeremy.gosnell]

I am feeding heavy on purpos, I am two days late doing my weekly water change, and as you stated I am going to let it ride till next week. I tested today and my nitrates are the lowest they have been in months. I will test again 3 days just to see. FYI I am at a 8 ppm today
Thank you for your quick answer.

8 ppm is a little high, it's not world's going to end high. You may notice some un-wanted algae growth. If that were to rise to 10 ppm, you could start seeing some color issues with various corals. Have you tested phosphate as well? What denitrification protocol do you have in place? My guess, is that if you're running a consistent 8 ppm of nitrate water changes are just acting as a band-aid anyhow. My nitrate doesn't change, it's consistently just enough of a tinge on a liquid test kit to show there is a trace of something, but not really dark enough to register as even 1 ppm. Many corals do best with a trace of nitrate in the water, but struggle once there is a measurable content for extended periods of time. My guess is you need to re-work your denitrification protocol.

 

[RudyB]

Great article. I was doing a bi-weekly water change even though I was reading near zero on all my tests. I was wondering if I could go longer without a water change. I am running a good protein skimmer, bio pellet reactor (feeding directly into the protein skimmer), carbon/GFO filter and a small refugium (used primary for growing and keep pods and RDL for PH stability). My ATO water is going through a kalk reactor. After reading your article I am going to see and test how long I can go before I see an up-tic in my readings. I will still replace my filter socks every three days and clean my skimmer when needed (usually about one week). I think your article was spot on and I hope that this test goes well and I change my water change schedule. I will test my water every week. Thank you for your wright up, it was very informative.

 

[jsker]

8 ppm is a little high, it's not world's going to end high. You may notice some un-wanted algae growth. If that were to rise to 10 ppm, you could start seeing some color issues with various corals. Have you tested phosphate as well? What denitrification protocol do you have in place? My guess, is that if you're running a consistent 8 ppm of nitrate water changes are just acting as a band-aid anyhow. My nitrate doesn't change, it's consistently just enough of a tinge on a liquid test kit to show there is a trace of something, but not really dark enough to register as even 1 ppm. Many corals do best with a trace of nitrate in the water, but struggle once there is a measurable content for extended periods of time. My guess is you need to re-work your denitrification protocol.

• I am running a bio pellet reactor for the past month and have dropped the nitrates down from 20+ to 8 and working toward 3-5 ppm. My corals look great and are growing at a fast rate. I had a issue with Green hair and that is gone, and just deal with a bit of maroon canyo. Po's are sitting .02 to .03 ppm. I just made a bunch of powder blue filter socks and I am going to start changing every 3 to 4 day weather they need it or not. I am thinking some of my nitrate issues are with not changing the filter socks until they are completely clogged with waste.
• I decided to do a 10% water change before reading your post this morning. Plan of action will be WC test in two days and get my No3's down to 3 to 5 ppm on my red sea test kit and then start to skip a week to see what happen to the system. I will give it 30 to 45 day, if there no change in the health of my system I try another week.
• Again thank you for you for you feed back

 

[FarmerTy]

8 ppm is a little high, it's not world's going to end high. You may notice some un-wanted algae growth. If that were to rise to 10 ppm, you could start seeing some color issues with various corals. Have you tested phosphate as well? What denitrification protocol do you have in place? My guess, is that if you're running a consistent 8 ppm of nitrate water changes are just acting as a band-aid anyhow. My nitrate doesn't change, it's consistently just enough of a tinge on a liquid test kit to show there is a trace of something, but not really dark enough to register as even 1 ppm. Many corals do best with a trace of nitrate in the water, but struggle once there is a measurable content for extended periods of time. My guess is you need to re-work your denitrification protocol.

I will offer an opposing view of nitrates, but mainly biased towards SPS-dominant tanks. You'll need around 5-8 ppm of nitrates to keep a nice healthy color for your SPS. Anything below that and they look faded and not as vibrant.

For no water changes, I did that for 3 years with my old 125-gallon and for my current 215-gallon, I've run 2 years now without water changes (with the exception that I overdosed Mg a couple months back and had to do some water changes to get it back to a normal level).

Similar setup as described in the article, GFO for phosphates, very large skimmer... I run a CaRX for foundation elements and also trace elements and instead of sulfur, I run biopellets for nitrates.

I say over the 5 cumulative years of no water changes on SPS-dominant tanks, I've keyed on in my personal opinion that the calcium reactor is the centerpiece for allowing this to work with my setup. Besides maintaining the foundation parameters of Ca, alk, and Mg, it also supplies strontium, potassium, and probably a slew of other elements in trace form.

Here's my tank that runs without water changes:

 

[jeremy.gosnell]

• I am running a bio pellet reactor for the past month and have dropped the nitrates down from 20+ to 8 and working toward 3-5 ppm. My corals look great and are growing at a fast rate. I had a issue with Green hair and that is gone, and just deal with a bit of maroon canyo. Po's are sitting .02 to .03 ppm. I just made a bunch of powder blue filter socks and I am going to start changing every 3 to 4 day weather they need it or not. I am thinking some of my nitrate issues are with not changing the filter socks until they are completely clogged with waste.
• I decided to do a 10% water change before reading your post this morning. Plan of action will be WC test in two days and get my No3's down to 3 to 5 ppm on my red sea test kit and then start to skip a week to see what happen to the system. I will give it 30 to 45 day, if there no change in the health of my system I try another week.
• Again thank you for you for you feed back

I would ensure the flow out of your bio-pellet reactor is going into a skimmer chamber. That could be the source of your cyanobacteria issue. As mentioned in my article on de-nitrification, bio-pellet reactors are home to a host of different microbial strains and some of them can cause cyanobacteria growth if they get into the water column.

A drop from 20+ is certainly a major step in the right direction. The elevated phosphates would concern me more than 8 ppm of nitrate. .02-.03 isn't much phosphate, but it is phosphate, which can stunt coral growth even in low amounts. I am guessing you don't run GFO and if not, have you ever considered it? There are lots of ways to remove phosphates, but GFO is cheap, easy and effective. It's actually the most readily used aquarium filtration media in production.

As for your nitrates, take a look at Polyp Lab's Reef Genesis kit. It consists of a bottle of dormant bacterial strains, a carbon source, amino acids and coral food. I think the bacteria and carbon source would help push those nitrates down a bit more, and I've found Polyp Lab's genesis to be more effective than other similar products. Once you complete a round of Genesis treatment, you could monitor your nitrates and see if the additional bacterial strains colonized your bio-pellets and are able to keep the nitrates down without further dosing. You may want to hold off the amino-acid and coral food until nitrate is down to 3 ppm or less and phosphate is undetectable.

It may seem counterproductive to dose bacteria and a carbon source, when bio-pellets are acting as your carbon source. However, you want to dose the bacteria, then the soluble carbon to form a bloom in the chamber where your reactor's pump is. That bloom will increase the amount of bacteria entering the reactor, where it can live long-term utilizing bio-pellets as a carbon source while assimilating nitrate.

 

[jeremy.gosnell]

No water changes is growing in popularity among SPS keepers and there are a few methods and systems that appeal to that. The Triton System states that water changes are actually a poor way to keep reef organisms largely because of instability concerns. To a degree it makes sense, as there aren't "water changes" in the ocean, where ocean levels drop by 30% and are replenished with all new ocean water of the same temperature and density. However the natural action of currents, the water cycle, etc does greatly impact the ocean's ability to maintain stable, clean and balanced water chemistry. I won't go as far as Triton is suggesting water changes are harmful and don't necessarily agree with that suggestion. I will say water changes are something that should be tailored to each individual tank and not subscribed on a "one time per week, per two week, etc" basis. Monitoring, observation and testing can help aquarists understand when their system's water needs changed, and how much change it responds well too.

One thing that is worth mentioning is the effect water changes have on ORP. There is extensive argument as to whether ORP can be considered a measure of water purity. The overall consensus is that just because water has a high ORP, doesn't necessarily mean it's of any greater purity (reef organism wise) than water that has a low ORP. However, it's commonly suggested that water with an ORP below 200 mv is waste laden and over 300 mv is oxidizing nutrient/waste build-up. I run ozone on my tank, so I monitor ORP 24/7 and the tank has an average ORP according to my Apex of 347.7 mv. The controller is programmed to kick off the ozone and the air pump that circulates it at 375 mv ORP. When I conduct a water change, my ORP drops from anywhere to 300-280 mv. By that measure, the new water is actually having an adverse effect when compared to the tank's existing water. My assumption has been that the water change water hasn't been treated with ozone and therefore has more elements within it, thus registering a lower ORP value. However, I closely monitor a whole range of values on my tank (about every value crucial to a reef system) every other day, and via dosing they stay in check. It's made me wonder if some salt mixes aren't adding things to the water that really aren't needed - or elements that may not have much of a value to our reefs. I would think that we would want our marine water to have the correct concentration of everything reef organisms need to grow and thrive, but nothing else. So if you have water with an ORP of 347.7 full of all the elements reef organisms need and you replace it with freshly made marine water that is nutrient/solid waste free, you would assume the ORP would either be lower or the same as the tank water. This is totally an anecdotal observation on my part, and as I mentioned there is debate as to whether ORP is in any way a measure of water quality/purity for reef aquarium purposes. For the record, I don't dose ozone with the hope of improving water quality but simply to clarify the water.

 

[FarmerTy]

I would ensure the flow out of your bio-pellet reactor is going into a skimmer chamber. That could be the source of your cyanobacteria issue. As mentioned in my article on de-nitrification, bio-pellet reactors are home to a host of different microbial strains and some of them can cause cyanobacteria growth if they get into the water column.

A drop from 20+ is certainly a major step in the right direction. The elevated phosphates would concern me more than 8 ppm of nitrate. .02-.03 isn't much phosphate, but it is phosphate, which can stunt coral growth even in low amounts. I am guessing you don't run GFO and if not, have you ever considered it? There are lots of ways to remove phosphates, but GFO is cheap, easy and effective. It's actually the most readily used aquarium filtration media in production.

As for your nitrates, take a look at Polyp Lab's Reef Genesis kit. It consists of a bottle of dormant bacterial strains, a carbon source, amino acids and coral food. I think the bacteria and carbon source would help push those nitrates down a bit more, and I've found Polyp Lab's genesis to be more effective than other similar products. Once you complete a round of Genesis treatment, you could monitor your nitrates and see if the additional bacterial strains colonized your bio-pellets and are able to keep the nitrates down without further dosing. You may want to hold off the amino-acid and coral food until nitrate is down to 3 ppm or less and phosphate is undetectable.

It may seem counterproductive to dose bacteria and a carbon source, when bio-pellets are acting as your carbon source. However, you want to dose the bacteria, then the soluble carbon to form a bloom in the chamber where your reactor's pump is. That bloom will increase the amount of bacteria entering the reactor, where it can live long-term utilizing bio-pellets as a carbon source while assimilating nitrate.

Promise I'm not trying to pick on you but 0.03 - 0.05 ppm of phosphate is typically the norm for an SPS tank. Suggesting to a person to aim for non-detectable is not advisable in my opinion as corals do need some phosphate for their biological processes.

 

[FarmerTy]

No water changes is growing in popularity among SPS keepers and there are a few methods and systems that appeal to that. The Triton System states that water changes are actually a poor way to keep reef organisms largely because of instability concerns. To a degree it makes sense, as there aren't "water changes" in the ocean, where ocean levels drop by 30% and are replenished with all new ocean water of the same temperature and density. However the natural action of currents, the water cycle, etc does greatly impact the ocean's ability to maintain stable, clean and balanced water chemistry. I won't go as far as Triton is suggesting water changes are harmful and don't necessarily agree with that suggestion. I will say water changes are something that should be tailored to each individual tank and not subscribed on a "one time per week, per two week, etc" basis. Monitoring, observation and testing can help aquarists understand when their system's water needs changed, and how much change it responds well too.

One thing that is worth mentioning is the effect water changes have on ORP. There is extensive argument as to whether ORP can be considered a measure of water purity. The overall consensus is that just because water has a high ORP, doesn't necessarily mean it's of any greater purity (reef organism wise) than water that has a low ORP. However, it's commonly suggested that water with an ORP below 200 mv is waste laden and over 300 mv is oxidizing nutrient/waste build-up. I run ozone on my tank, so I monitor ORP 24/7 and the tank has an average ORP according to my Apex of 347.7 mv. The controller is programmed to kick off the ozone and the air pump that circulates it at 375 mv ORP. When I conduct a water change, my ORP drops from anywhere to 300-280 mv. By that measure, the new water is actually having an adverse effect when compared to the tank's existing water. My assumption has been that the water change water hasn't been treated with ozone and therefore has more elements within it, thus registering a lower ORP value. However, I closely monitor a whole range of values on my tank (about every value crucial to a reef system) every other day, and via dosing they stay in check. It's made me wonder if some salt mixes aren't adding things to the water that really aren't needed - or elements that may not have much of a value to our reefs. I would think that we would want our marine water to have the correct concentration of everything reef organisms need to grow and thrive, but nothing else. So if you have water with an ORP of 347.7 full of all the elements reef organisms need and you replace it with freshly made marine water that is nutrient/solid waste free, you would assume the ORP would either be lower or the same as the tank water. This is totally an anecdotal observation on my part, and as I mentioned there is debate as to whether ORP is in any way a measure of water quality/purity for reef aquarium purposes. For the record, I don't dose ozone with the hope of improving water quality but simply to clarify the water.

That's real interesting Jeremy. I'll have to take more of a scrutinized look at my ORP levels in my display tank once I get my ORP probe hooked up. I've been running one on the frag tank just because I had an open pH probe port on the unit but both probe ports on my display tank Apex were being used for the Calcium reactor. I pickup up a used PM1 unit with ORP probe so I can start keeping an eye on trends with my display tank now.

 

[tweeter]

I will offer an opposing view of nitrates, but mainly biased towards SPS-dominant tanks. You'll need around 5-8 ppm of nitrates to keep a nice healthy color for your SPS. Anything below that and they look faded and not as vibrant.

For no water changes, I did that for 3 years with my old 125-gallon and for my current 215-gallon, I've run 2 years now without water changes (with the exception that I overdosed Mg a couple months back and had to do some water changes to get it back to a normal level).

Similar setup as described in the article, GFO for phosphates, very large skimmer... I run a CaRX for foundation elements and also trace elements and instead of sulfur, I run biopellets for nitrates.

I say over the 5 cumulative years of no water changes on SPS-dominant tanks, I've keyed on in my personal opinion that the calcium reactor is the centerpiece for allowing this to work with my setup. Besides maintaining the foundation parameters of Ca, alk, and Mg, it also supplies strontium, potassium, and probably a slew of other elements in trace form.

Here's my tank that runs without water changes:

Nice! Thanks for sharing!And I love your angel!

 

[FarmerTy]

Thanks! I have 5 angels these days. Emperor, majestic, flame, potters, and a red sea regal. I'm infatuated with them now!

 

[Roberto CRC]

Personally I find a lot of sense to what you say in the article, I found explanations to some points I have always had with doubts about the change or not water.

Thanks

 

[Mr tap water]

If I stopped doing water changes my concerns would be The amount of minor elements that would be depleted Over a set time period ,being that there is around 70 of them or thereabouts a lot of the minor ones can get used up at different rates, so do we really know The affects it has on the marine life in the long run being starved of these minor elements. As I believe all these elements are here for a reason and every one of them keep things in balance, for one reason or another.

 

[FarmerTy]

If I stopped doing water changes my concerns would be The amount of minor elements that would be depleted Over a set time period ,being that there is around 70 of them or thereabouts a lot of the minor ones can get used up at different rates, so do we really know The affects it has on the marine life in the long run being starved of these minor elements. As I believe all these elements are here for a reason and every one of them keep things in balance, for one reason or another.

I'm your perfect test subject, 5 years between two tanks of no water changes. If something was in excess or was depleted could cause harm to the livestock, I would have seen it by now I would assume.

Again, I think the glue is the calcium reactor. It no doubt is supplying some of these trace elements we don't test for or don't dose back into the system.

 

[chefjpaul]

I'm your perfect test subject, 5 years between two tanks of no water changes. If something was in excess or was depleted could cause harm to the livestock, I would have seen it by now I would assume.

Again, I think the glue is the calcium reactor. It no doubt is supplying some of these trace elements we don't test for or don't dose back into the system.

My only concern with doing away with w/c would be just getting out all the garbage, not a depletion as that can be corrected.

 

[FarmerTy]

My only concern with doing away with w/c would be just getting out all the garbage, not a depletion as that can be corrected.

I would agree that it is a valid concern. My counter is this, imagine how much garbage accumulated in the last two years in my tank. Only physical removal method in my tank is a skimmer. That means all that food, the chemicals, and fish poop reside in my system that isn't skimmed out initially before breakdown.

I use the GFO to take care of the phosphates, the carbon dosing to take care of nitrates, and activated carbon for organics (okay, sure, I'll give a small nod to activated carbon being a physical removal method too).

Surely if there was any particular contaminant to have built up enough to become toxic, it would have done it in two years of daily tank activities.

Here's an example of how much I feed 6 days a week. On top of that, I also have my auto feeder drop pellets 5 times a day.



I'm keeping delicate SPS, gonis, and angels in this system. If it's not breaking under the strains I put my tank through and the amount of delicate creatures I have, I think the average tank will be just fine. Obviously this is a blanket statement as other systems may be exposed to contaminants that aren't a factor in my tank.

Thats where like the OP mentioned, you have to listen to your system and tailor it.

 

[chefjpaul]

I would agree that it is a valid concern. My counter is this, imagine how much garbage accumulated in the last two years in my tank. Only physical removal method in my tank is a skimmer. That means all that food, the chemicals, and fish poop reside in my system that isn't skimmed out initially before breakdown.

I use the GFO to take care of the phosphates, the carbon dosing to take care of nitrates, and activated carbon for organics (okay, sure, I'll give a small nod to activated carbon being a physical removal method too).

Surely if there was any particular contaminant to have built up enough to become toxic, it would have done it in two years of daily tank activities.

Here's an example of how much I feed 6 days a week. On top of that, I also have my auto feeder drop pellets 5 times a day.



I'm keeping delicate SPS, gonis, and angels in this system. If it's not breaking under the strains I put my tank through and the amount of delicate creatures I have, I think the average tank will be just fine. Obviously this is a blanket statement as other systems may be exposed to contaminants that aren't a factor in my tank.

Thats where like the OP mentioned, you have to listen to your system and tailor it.

Oh I agree, I wasn't really referring to chemical compounds, mainly true filth, detritus etc..
stirring sand bed? Filter socks etc?
Your tank is very clean.

Currently Im only running a bb tank until house remodeling is done, thinking of keeping new tank the same, can't stand all the garbage the accumulates.

 

[FarmerTy]

Oh I agree, I wasn't really referring to chemical compounds, mainly true filth, detritus etc..
stirring sand bed? Filter socks etc?
Your tank is very clean.

Currently Im only running a bb tank until house remodeling is done, thinking of keeping new tank the same, can't stand all the garbage the accumulates.

You should see my sump ChefPaul! There's a inch of detritus, sometimes more down there. [emoji4] A lot of good flow in the display keeps all that junk down in the sump but stuff still accumulates from time to time in the display. Conchs help a lot as well as sea cucumbers to keep it from settling too much on the sand.

 

[o2manyfish]

You made some great points.

In my opinion the necessity for water changes is usually because of deficient biological filtration. These days people like the 'minimal' rock look in their tanks, and have sexy looking sumps that are really just a little box of water to set a skimmer in. Then they add their fish, feed their fish, and then start adding devices, chemicals, contraptions to try to maintain water quality. They have to constantly test and correct.

Going back 40 years this was the basis of the saltwater fish hobby. Then came the idea of a "mini-reef". Rather than relying on just an undergravel filter for biological filtration and water changes, we added living rock - and now with more surface area and bio diversity we had an eco-system that could support itself.

For the first 30 years I kept a "reef" aquarium, I didn't feed it. I had a robust fish collection, but I relied upon the what the reef produced to feed the fish. Tangs, angels, gobies, clowns, blennies - all survived and flourished without adding food.

Just by stating the decades I have kept aquariums, I am old school, and a prima donna. I like using lots of rock, I keep rock in my sump, I run a fluidized sand filter for additional biological filtration. I have what most would consider a successful reef (Reefbuilders wrote an article about my tank this month https://reefbuilders.com/2016/07/20/dave-botwins-reef-is-totally-packed-with-fish-corals/)

In the past 3 years I have done one water change of 100 gallons.... Nope not pulling your leg.

My system volume is 1100 gallons. My 400g display tank has about 130 fish, and more corals than you can count.My filtration consists of live rock (1000+lbs), a 5' fluidized sand filter, enough chaeto to fill about a 40g tank, and currently about 12 square feet of xenia. The majority of my system is outside, and I use evaporative cooling. In the summer I am evaporating over 35 gallons a day and replacing it with Kalkwasser. I run a calcium reactor. And I have a 12 year old Dilapidated Deltec 702 skimmer.

I wasn't dosing or balling or adding or checking. Sometimes I would dump some potassium, sometimes some iodine, sometimes nothing at all. And I am too lazy to test anything. Most of my testing comes from local hobbyists coming over to play with their test kits.

I was fortunate to be one of the first people to get access to the Triton water testing. That was about 18 months ago. At that point my tank was about 18 months since a horrible kalkwasser crash and hadn't had a water change. When I got my first Triton Results I was so excited about finding out how I could tweak my tank.... I mean a packed reef system, with no water changes or dosing should have a lot of issues.

But the first test came back... And there was nothing to tweak. My phosphates were ,48 at the time. And my tank was doing well.

So I bought some GFO and said I will lower my phosphates. But then after a month, I got lazy and forgot about it.

I have been running Triton Tests about every 3 months. No water changes.

About a year ago I started dosing Triton Base Elementz -- Just as a test. 60 days later I ran a Triton test -- The water results weren't any different. But the growth of my corals had taken off.

At the beginning of this year my phosphate levels were 2.4 - not ,024 but 2.4. My alkalinity was 14. My corals looked amazing. I had no algae issues. My outdoor frag tank didn't even have algae on the frag racks. Nitrates were in the mid 20's.

In the past year I have had spawning flame back angels, spawning damsels, spawning mandarins, spawning clowns, spawning bangai cardinals, spawning red scooter blennies and spawning Bellus angels.

I credit this to massive biological filtration... those darn xenia that everyone curses, are just a huge filter in my opinion. And with all this biological filtration mother nature does a much better job of maintaining my reef than I can.

My work sometimes gets a bit crazy. In April to May of this year other than wipe algae off the front glass I didn't do anything to my reef. No maintenance, food, for 6 weeks. And everything did great.

I had some reef geek friends over this past weekend and we were admiring the new outdoor frag tank I installed. The frag tank is bare bottom, has 2 sheets of egg crate sitting about 3" off the bottom of the tank. Last month my old frag tank blew a seam (Livestock was saved by the cursed xenia getting sucked into the 3/4" gap and stopping the tank from draining). All the corals and fish got moved to a temporary frag tank, and then 2 weeks ago, they got moved back into a new frag tank. The frag tank has a maturing Imperator angel, Yellow belly regal angel, Juvenile Navarchus Angel, Colini Angel, Goldflake Angel, 2 tangs, 2 clowns and a dozen damsels. These fish are all so fat and healthy. And I don't feed the tank. All those angels are finding enough to eat off of just egg crate to be fat and happy ..... once again mother nature does better than I can.

If you design an aquarium, with the biological filtration more than capable of handling your fish load - then you don't have anything that needs exporting (in my opinion). If you take it to the next step and build a reef aquarium, with biological filtration capable of handling your fish load and providing the sustenance for your fish, and you replenish what the corals are consuming.... Then what is left to export?

I'm all for aquarium gadgets, but at the root of the reef - is biology.

Dave B

 

[jeremy.gosnell]

While I know of some aquarists that run a bit of phosphate in their tank simply because they cannot drop levels down to undetectable, I've not known anyone that considers .03-.05 phosphate concentration the norm. Most of the aquarists I know that run SPS dedicated tanks, are following the principles of ULNS. But, you learn something every day. One of the issues with phosphate is that there isn't just one type of phosphate. In fact, there are different types of phosphate and various liquid test kits are providing aquarists a "rough estimate" of phosphate concentration. The same is true of liquid test kits for other elements, and usually they provide a figure that is "round-about" the water's actual concentration. They are most useful to determining if your aquarium's parameters are stable. Test kits don't provide a breakdown of what types of phosphate are present in our aquarium water. It's without a doubt that corals need some nutrient content in order to grow, as it encourages the growth of zooxanthellae. It's this reason that ULNS keepers are constantly adding amino-acids and proteins to the water, encouraging cellular development. For me personally, I've found a ULNS the best way to operate a reef and have a wide degree of control over speed of growth, coloration, etc. However, it's not for everyone and comes with ample risk. Depleting nutrients too quickly or too broadly can cause rapid tissue necrosis.

Biology is most certainly the foundation of a reef tank. If you set up a tank that can naturally provide for every needed function (denitrification, crucial elements, etc) life will be much easier. 10 years ago, it was uncommon to see reef tanks filled with numerous large fish. Now they aren't uncommon. The reason they weren't 10 years ago, was simply because the technology didn't exist to filter the waste generated by some many fish. You had to follow bio-chemical processes or you failed at reef keeping. New technology often utilizes those same bio-chemical processes, it just does so more efficiently and within smaller spaces. It also carries the risk that if the bacteria within a reactor or compressed filter media dies, the fallout can be severe.

 

[jeremy.gosnell]

That's real interesting Jeremy. I'll have to take more of a scrutinized look at my ORP levels in my display tank once I get my ORP probe hooked up. I've been running one on the frag tank just because I had an open pH probe port on the unit but both probe ports on my display tank Apex were being used for the Calcium reactor. I pickup up a used PM1 unit with ORP probe so I can start keeping an eye on trends with my display tank now.

Remember that ORP isn't a 100% verified measure of water purity. Some aquarists use it that way and others don't even monitor ORP. I monitor it because I use ozone and an ORP controller is the safest way to do so. However, I've personally noticed that ORP levels are indicative to how my corals appear. Usually when my ORP is up above 300-350 mv - the corals appear great and are extended and beautiful. If it drops down closer to 250 some are closed up, etc. That is entirely anecdotal and could be totally unrelated, but it's a personal observation I've made over the years. When I worked in public aquaria ozone was commonly used on a wide scale, both to maintain water quality in large displays and to sterilize water during a mass filtration-cleaning period. In this case, ORP was run up to 600+ mv then given time to off-gas before being used. The goal was to kill any potential parasites within the water.