To Water Change or Not, Nutrient Export

[Angel_V_the_reefer]

You're on the right track with your questioning, it's just that no one has come up with a really definitive answer as to why corals seem to look better to many after a water change.

And for some, the opposite is true so we can also throw that into the mix.

I agree !

My thoughts on the subject...

A system's diverse microbial community is of paramount importance since without it all the fancy equipment in the world won't achieve a successful reef aquarium.

Exactly, without these bacterias we wouldn't have nutrients nor nutrient exports that create this cycle that enables coral reefs to exist

Having said that, excellent/durable equipment (and backups, if possible) contributes to long term success/longevity.

Having the least amount of equipment (that still provides for a favorable reef aquarium environment) helps to prevent 'reefer burnout' (less fiddling/repair/replacement/chance of mistakes) and also makes the system more robust (minimization of failure points).

Given enough time (and some restraint from us to not constantly tweak and meddle) the simplest of systems often outlast all others.

I personally have always and still to this day perform water changes. This is really my only method of exporting nutrients, along with Mechanical filtration (filter floss) and Biological filtration.

I have not yet come to the conclusion of whether it is really worth it to invest in a protein skimmer, Algae scrubber, refugiums, etc, etc.

 

[Angel_V_the_reefer]

I think it's trace elements.

A water change can only add in a % of the trace elements back, and many(I guess maybe all) salts are somewhat lacking in the trace elements. So you do a water change, and you replenish part of them. But your coral likely use them all up before your next water change. So each time you do the water change, they get the temporary boost, and if they were depleted, you only replenish 20% of whatever the salt has.

This has been an anecdote of mine as well. IME my corals look great for 3 days and the rest of the week they look Good but not as great as after a WC. I would believe Trace elements to play a big factor in this.

Meanwhile people who dose trace elements maintain that effect full time, and water change can often times reduce those elements. But there is so much going on, it's really hard to measure, I'm no scientist.

I've seen this effect in my anemone tank with macro elements. It's a 29g tank, with just some RBTA and 2 clownfish, trash palys and some xenia. I rarely do water changes on it, maybe 3 a year. I don't dose anything on it, not even alk/cal. I let algae grow in the tank and remove it about once a month for nutrient removal.

It does not grow coraline really. It doesn't have the cal/alk to do so. However, after I do a water change, some will grow here and there for a short time after(and then the urchins eat it up). Then it gets to a point where it stops growing after using up the cal/alk.

I think the same thing happens with trace elements. Unlike the macro, the coral can still stay alive without them, but they will only survive, not thrive. Some still grow, but not as colorful etc. Which was basically my experience with water changes in the past, where they would perk up after a water change. They would grow for a short time after the water change, then slow down.

I would agree. This is the only thing that comes to mind with water changes. Maybe even gettin rid of detritus to limit nutrient breakdown, but that would require weekly WC .

Im still unsure how efficient many nutrient exports are in this hobby. Theres just so many opinions and testimonies out there to know the truth

 

[Chortanator]

I know a lot of people have already given their two cents here, but I'll share mine as well:

I neglected my tank for nearly a year and only did top-ups in my ATO. During that time, my nitrates skyrocketed to over 100. When I realised how awful my tank looked, I knew I had to make some changes. Large water changes are the easiest way to get rid of large amount of nitrates. I was doing 50% water changes 2x a week for about a month before my nitrates were sub-10. Somewhere during those water changes, my chaeto remembered that it was supposed to grow, and has been growing like a weed ever since.

I have a skimmer, a Bubble Mag Curve 5, but I always have issues with it either overflowing or not making the bubbles go high enough without me touching it at all, so I stopped using it. I also had a bag of GFO in there that I've since taken out because my nitrates bottomed out.

So currently, I only have chaeto as a nutrient export, and I monitor my nitrates with weekly tests (Red Sea and Salifert). I currently dose Red Sea Foundations A & B (Calcium and Alk) and the Red Sea trace element kit whenever I feel like it (which is not usually)

 

[Angel_V_the_reefer]

I know a lot of people have already given their two cents here, but I'll share mine as well:

I neglected my tank for nearly a year and only did top-ups in my ATO. During that time, my nitrates skyrocketed to over 100. When I realised how awful my tank looked, I knew I had to make some changes. Large water changes are the easiest way to get rid of large amount of nitrates. I was doing 50% water changes 2x a week for about a month before my nitrates were sub-10. Somewhere during those water changes, my chaeto remembered that it was supposed to grow, and has been growing like a weed ever since.

When I had high nitrates starting off as a new reefer, I was always told to rely on WC on a nano, so did. I will say they do help quite a lot especially when a tank is barely maturing. That being said, the water changes do have to be big WC.

I can't imagine how much water is needed in a bigger system 100+ gallons.

I have noticed, however, on smaller tanks, 30% water changes weekly help maintain nitrates low (IME nitrates would stay around 25 ppm my first year and after 30% water change would drop to 10-15 ppm using a Salifert test kit).

on a 20 gal with net 15 gallons of actual volume, that is only 5 gallons. Imagine now a bigger system, I would hate to have to change out even more water.

I have a skimmer, a Bubble Mag Curve 5, but I always have issues with it either overflowing or not making the bubbles go high enough without me touching it at all, so I stopped using it. I also had a bag of GFO in there that I've since taken out because my nitrates bottomed out.

I believe GFO is a great way to maintain PO4 at your desired levels, along with proper feeding regimen.

So currently, I only have chaeto as a nutrient export, and I monitor my nitrates with weekly tests (Red Sea and Salifert). I currently dose Red Sea Foundations A & B (Calcium and Alk) and the Red Sea trace element kit whenever I feel like it (which is not usually)

This has been an idea in my head as well, however I have an AIO and I have heard fuses require loads of water volume to grow, can you attest by that ?

 

[Dan_P]

Are water changes still necessary with today’s knowledge on reef chemistry and it’s effectiveness?

are water changes really effective in reducing nitrates and maybe even some phosphates ?

if we now have many ways of nutrient export and ways to dose trace and major elements, why water change (unless to rid your tank of something foreign).

what ways can one rely on nutrient export and are there methods that really don’t help ? I’ve heard some rumors that protein skimmers don’t remove much proteins in the water. Could this be true ?

Wet skimming can quickly remove dissolved and particulate organic carbon quite well. Removing 1% of the system’s volume daily in skimmate is far more effective than a daily 1% water change for exporting waste. With this level of throughput, skimmers become fouled far less often, making cleaning a bimonthly or monthly chore. The downside of such a large daily volume loss is that automatic freshwater replacement devices end up reducing the salinity of a system. As a result, the hobby dry skims, making the skimmer possibly a useless nutrient export device. This not to say that skimmers are major exporters of nitrate and phosphate, but there is more to clean water than low nitrate and phosphate.

 

[rtparty]

Are they necessary? No

Do they replace trace elements? No

Are they good for reducing N and P? Only large water changes. If you have 50ppm nitrates and want to lower them, a 50% water change will only lower them to 25ppm. So no, they aren't good for this either.

So what are water changes good for? Removing organic and inorganic compounds we can't test for. But how do we know what they're actually doing if we can't test for it? They are also good for the salt companies and their bank accounts. They're good for wasting water.

We've moved well past water changes but 90% (or more) of the hobby hasn't caught up

 

[Chortanator]

I have noticed, however, on smaller tanks, 30% water changes weekly help maintain nitrates low (IME nitrates would stay around 25 ppm my first year and after 30% water change would drop to 10-15 ppm using a Salifert test kit).

My tank is 55 gallons, and changing that much out weekly is a lot of water and a lot of heavy lifting. I think that if you go heavy on the live rock and light on the feeding even in a nano tank, a 30% water change shouldn't be necessary.

I believe GFO is a great way to maintain PO4 at your desired levels, along with proper feeding regimen.

GFO is mostly for PO4, but I've heard that it also lowers nitrates which seems to be the case, unless it's just my chaeto that's completely sucking the nitrates out of my tank.

This has been an idea in my head as well, however I have an AIO and I have heard fuses require loads of water volume to grow, can you attest by that ?

Do you mean a fuge? I don't think they necessarily need a large water volume. I have a Red Sea Reefer 250, which is a 55g DT + 11g sump. About a quarter of that sump is a dedicated fuge, and my inactive skimmer takes up about 25% of it. My lights just went out but I can take a picture of it in the morning. Some people like to tumble their chaeto, but I don't really know what that accomplishes. My sump is relatively medium-flow and the chaeto stays still so that I can grow pods.

 

[Angel_V_the_reefer]

Wet skimming can quickly remove dissolved and particulate organic carbon quite well. Removing 1% of the system’s volume daily in skimmate is far more effective than a daily 1% water change for exporting waste. With this level of throughput, skimmers become fouled far less often, making cleaning a bimonthly or monthly chore. The downside of such a large daily volume loss is that automatic freshwater replacement devices end up reducing the salinity of a system. As a result, the hobby dry skims, making the skimmer possibly a useless nutrient export device. This not to say that skimmers are major exporters of nitrate and phosphate, but there is more to clean water than low nitrate and phosphate.

I agree. This is also a great topic to mention. What exactly makes up our water column? I would love to see articles on this topic for everyone to give a good read.

 

[Angel_V_the_reefer]

Are they necessary? No

Do they replace trace elements? No

Are they good for reducing N and P? Only large water changes. If you have 50ppm nitrates and want to lower them, a 50% water change will only lower them to 25ppm. So no, they aren't good for this either.

So what are water changes good for? Removing organic and inorganic compounds we can't test for. But how do we know what they're actually doing if we can't test for it? They are also good for the salt companies and their bank accounts. They're good for wasting water.

We've moved well past water changes but 90% (or more) of the hobby hasn't caught up

This is a big one. Although WC can be great for nanos, no one likes to do them for bigger tanks. I believe its way too much of a hassle.

I believe we have the right tools to move away from WC too. With so many dosing options to maintain elements stable, there isn't really a need for WC, unless you're looking for nutrient export, which is a great option, but isn't the easiest one.

Now the question stands, what ways are great to reduce N or P and/or altogether ?

 

[Angel_V_the_reefer]

My tank is 55 gallons, and changing that much out weekly is a lot of water and a lot of heavy lifting. I think that if you go heavy on the live rock and light on the feeding even in a nano tank, a 30% water change shouldn't be necessary.


GFO is mostly for PO4, but I've heard that it also lowers nitrates which seems to be the case, unless it's just my chaeto that's completely sucking the nitrates out of my tank.

I believe it only targets PO4. I believe the Chaeto utilizes a bit of both.

Do you mean a fuge? I don't think they necessarily need a large water volume. I have a Red Sea Reefer 250, which is a 55g DT + 11g sump. About a quarter of that sump is a dedicated fuge, and my inactive skimmer takes up about 25% of it. My lights just went out but I can take a picture of it in the morning. Some people like to tumble their chaeto, but I don't really know what that accomplishes. My sump is relatively medium-flow and the chaeto stays still so that I can grow pods.

Yes I meant Fuge haha, I would have to do my own research. I also like the idea of an Algae Scrubber as well, im curious however, if it would grow algae in an algae free system, such as a pretty new set up.

 

[rtparty]

This is a big one. Although WC can be great for nanos, no one likes to do them for bigger tanks. I believe its way too much of a hassle.

I believe we have the right tools to move away from WC too. With so many dosing options to maintain elements stable, there isn't really a need for WC, unless you're looking for nutrient export, which is a great option, but isn't the easiest one.

Now the question stands, what ways are great to reduce N or P and/or altogether ?

Coral (people often overlook and underestimate this one), refugium, algae scrubber, carbon dosing, protein skimmer, filter roller/socks/floss

 

[john92708]

I don't do weekly or monthly WC on my 14 AIO nano but instead rely mainly on a DIY algae scrubber for nutrient export. I do have a protein skimmer but it's not removing anything other then oxygenating the water. I'm not using chemical filtration either. Plan is to do a large WC only when something went wrong. Been 6 months and all the corals mostly soft and fish are looking good. snail keep the tank clean and remove what little algae that grow in the display.

 

[Angel_V_the_reefer]

Coral (people often overlook and underestimate this one), refugium, algae scrubber, carbon dosing, protein skimmer, filter roller/socks/floss

Coral is a big one ! I like the idea of a fleece roller, I am debating whether to add a sump for my soon to be nuvo 20 build, however filter floss is not a problem to me, as I like to make a template of my floss holder and pre cut weeks of filter floss, making it as easy as dump out and replace !

I have given an Algae Scrubber a thought as I believe it would be a easier way to control nutrient export, with the flip of a switch !

How easy or hard would it be to grow algae out on a fairly new reef ?

 

[Angel_V_the_reefer]

I don't do weekly or monthly WC on my 14 AIO nano but instead rely mainly on a DIY algae scrubber for nutrient export. I do have a protein skimmer but it's not removing anything other then oxygenating the water. I'm not using chemical filtration either. Plan is to do a large WC only when something went wrong. Been 6 months and all the corals mostly soft and fish are looking good. snail keep the tank clean and remove what little algae that grow in the display.

What parameters does your Scrubber allow you to maintain? Do you find it easy to grow algae?

Algae Scrubbers seem very cool to me nd I have considered maybe even building one as a way to have options to my nutrient export, instead o solely relying on WC, Bio and Mech filtration to export nutrients.

 

[Nano sapiens]

When I had high nitrates starting off as a new reefer, I was always told to rely on WC on a nano, so did. I will say they do help quite a lot especially when a tank is barely maturing. That being said, the water changes do have to be big WC.

I can't imagine how much water is needed in a bigger system 100+ gallons.

I have noticed, however, on smaller tanks, 30% water changes weekly help maintain nitrates low (IME nitrates would stay around 25 ppm my first year and after 30% water change would drop to 10-15 ppm using a Salifert test kit).

on a 20 gal with net 15 gallons of actual volume, that is only 5 gallons. Imagine now a bigger system, I would hate to have to change out even more water.

I would agree that when a nano is young that larger water changes are typically beneficial. At this early stage I was doing around 15-20%/wk if I remember correctly.

But as the more mature years went by, a total volume change of 10%/wk (5%/2x/wk) brought good results (1g/wk total).

And now in it's even more mature phase I'm down to 7%/wk (3.5% - 2x/wk) making a grand total of 2/3g/wk total and the corals look better than ever

I don't use water changes directly to control PO4/NO3, but they do allow me the chance to vacuum the sand bed weekly to remove some of the excess organic buildup and stimulate the resident microorganisms to replenish themselves (a continuous cycle of nutrient sequestration/nutrient removal, one might say).

 

[Angel_V_the_reefer]

I would agree that when a nano is young that larger water changes are typically beneficial. At this early stage I was doing around 15-20%/wk if I remember correctly.

I was at 30% starting off on a new reef. I Definitely believe that for a nano, WC are great options

But as the more mature years went by, a total volume change of 10%/wk (5%/2x/wk) brought good results (1g/wk total).

And now in it's even more mature phase I'm down to 7%/wk (3.5% - 2x/wk) making a grand total of 2/3g/wk total and the corals look better than ever

Maturation of microbial life! This is the most important IME

I don't use water changes directly to control PO4/NO3, but they do allow me the chance to vacuum the sand bed weekly to remove some of the excess organic buildup and stimulate the resident microorganisms to replenish themselves (a continuous cycle of nutrient sequestration/nutrient removal, one might say).

Do you have any pictures of your reef ?

 

[john92708]

What parameters does your Scrubber allow you to maintain? Do you find it easy to grow algae?

Algae Scrubbers seem very cool to me nd I have considered maybe even building one as a way to have options to my nutrient export, instead o solely relying on WC, Bio and Mech filtration to export nutrients.

I stop testing my nano. it's super easy and you should try it. you just need a refugium LED light. I used the one from CheatoMax. I find the algae scrubber to be very efficient at removing nutrients. I was having Dino and GHA problem even with the skimmer running 9 hours a day. About 2 weeks after installing the scrubber, I notice Dino and GHA stop growing in the display and skimmer stop removing stuff. no other change were made to my routine.

 

[Jrswish]

Give your fish a bath, by doing a WC. For me people who don’t do water changes are simply doing it because they’re lazy

 

[Nano sapiens]

I was at 30% starting off on a new reef. I Definitely believe that for a nano, WC are great options



Maturation of microbial life! This is the most important IME



Do you have any pictures of your reef ?

FTS Dec 2021:

 

[Jeffcb]

I am going to do a 15% water change soon. Last one was in November.