Do you consider a water change to be an effective type of aquarium filtration method?

[ying yang]

I voted no,as understand water changes will remove the likes of nitrate but don't class that as filtration but depends on what terminology used so could be but I think no just on term filtration,filtration. To me is some kind off appliance that holds media or live rock/sand and the likes,but my head really weird and very logical and get hooked up on what words used pffft ( does my own head in sometimes) ^_^

 

[Randy Holmes-Farley]

You must be awfully sure about yourself, might want to think asking what he meant first ^^
It all depends on what he meant with "proper levels" and "long term pollution".

If "proper levels" mean "ocean levels", where the water has no accumulation due to the vast reservoir and natural filtering cycles, he is actually right. No amount of thinning, maybe short of something like 100% per day with continuous exchange, will bring pollution levels down to baseline.

If "long term pollution" means a constant accumulation of pollutants that the tank can't cycle itself fast enough, like nitrate without enough anaerobic bacteria and/or plants, no water change will get rid of the accumulation itself, it will only fight the symptoms (e.g. buildup).

At least that's as far as I understand ^^

Yea, I am quite certain about my math and my answer being an appropriate response to an incorrect assertion (his #2).

FWIW, you seem to be the one who didn’t understand the post of mine, but perhaps that was partly my fault for not directing you to his #2 comment to properly understand my response,

 

[Costareefer]

If rock is considered filtration then siphoning the detritus in and around rock so it can perform its action effectively is part of the filtration process. You can filter through skimming or whatever all you want but you will never come close to cleaning all the detritus

 

[Cherie cook]

Water changes may be the only way to remove certain organics.

Could you expand upon this a bit…I’m really interested.

 

[KrisReef]

Everytime I jump in the ocean I ask myself: "When is somebody going to do a waterchange on the ocean?" The fish have been living in this same water for millions of years and someday this ocean is going to crash from neglect!"

When I snorkel on a reef, I try to observe the currents and flows of water in the environment. The corals on the forereef are getting water changes continually. That movement brings in and removes all kinds of things as it moves over the reef. The reef maybe more of a filter of the water than the water movement is a filter of the reef, but they are both working together, as designed.

 

[Randy Holmes-Farley]

Could you expand upon this a bit…I’m really interested.

Many of the organisms we keep intentionally secrete organics, many of which are released specifically to kill or otherwise deter competitors for space, food, etc.

Some of those are potentially accumulating in reef tanks, and we may have no effective way to remove them, aside from water changes. Organic binders such as GAC and Purigen only remove certain types of organic matter. Skimmers remove other types. There are other organics that will not be effectively removed by these processes.

I discuss organics, including toxins, here:

Organic Compounds in the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

 

[vlangel]

I know a lot of folks have doubts to the effectiveness of water changes but I became a believer when I worked for a lfs and did aquarium maintenance. I have seen tanks run for decades without any issues. Not just my own tanks but customer's tanks as well.

 

[BionicReef73]

We started talking about aquarium filtration yesterday and someone reminded me that I forgot to add water changes as a filter option. There have been quite a few "tests" done on the effectiveness of water changes as it pertains to the exporting of nutrients or filtering water. Let's discuss!

Do you consider a water change to be an effective type of aquarium filtration method? Why or why not?

image via @CoralReefer2110

Yes if you are doing it regularly and closer to a 50% otherwise , I believe it's not making enough of an impact on the nutrient levels

 

[firechild]

Many of the organisms we keep intentionally secrete organics, many of which are released specifically to kill or otherwise deter competitors for space, food, etc.

Some of those are potentially accumulating in reef tanks, and we may have no effective way to remove them, aside from water changes. Organic binders such as GAC and Purigen only remove certain types of organic matter. Skimmers remove other types. There are other organics that will not be effectively removed by these processes.

I discuss organics, including toxins, here:

Organic Compounds in the Reef Aquarium by Randy Holmes-Farley - Reefkeeping.com

I think this is particularly important for people who keep soft corals, zoanthids and macro algae (refugium anyone?) as these generally produce more of these kinds of chemicals than Acroporids for example.

Toxins, Venoms and Inhibitory Chemicals in Marine Organisms

Competition and the requirement to kill prey quickly means that venoms in marine species are far more powerful than similar venoms in terrestrial organisms.

reefs.com

 

[pledosophy]

You must have taken different math classes than I did. lol

Math tells me it does reduce pollution long term.


Water Changes in Reef Aquaria by Randy Holmes-Farley - Reefkeeping.com

example:

Figure 3. Nitrate concentration as a function of time when performing water changes of 0% (no changes), 7.5%, 15% and 30% of the total volume each month. In this example, nitrate is present at 100 ppm at the start, and is accumulated at a rate of 0.1 ppm per day when no water is changed.

You should have taken simple math with the rest of us. Maybe I should have worded it differently. Water changes will reduce pollution but not eliminate it long term. Eventually the pollution levels will climb. They can not be solely relied on.

Funny enough I actually learned this from you in an article you did for Reefkeeping 15-20 years ago. I am going to round out the decimals to make it easier for us simple math people.

If your tank makes 10ppm of nitrate a week, and you do a 10% water change the tank still has 9ppm of nitrate left.

Week two the tank makes 10ppm of nitrate again, but there is still the remaining nine from the week before. So the nitrate is at 19ppm. That 10% water change gets you down to 17ppm.

Week three, tank makes another 10ppm of nitrate, and you had the 17ppm from before for 27ppm. A 10% change gets you down to 24ppm.

Week 4 tank makes another 10ppm of nitrate, add it to the 24ppm that was in the tank puts the tank at 34ppm nitrate. A 10% change brings the tank down to 31ppm

Week 5- tank owner posts on R2R asking why they have algae when their levels are perfect and they do weekly 10% water changes.

This same logic can be applied to using water at NSW levels to dose tanks, but in reverse.

 

[s_spowart]

A water change is normally only needed if something is wrong with your setup.
If you have an effective nutrient export, and replace all the elements needed through dosing then water changes only stress the livestock.
That said, fir a small aquarium it may be necessary to continue changing water as it is harder to get the system stable but for a 100 gallon or larger tank, best have a refugium and suitably sized skimmer, and a good testing regime. Then just use a dosing pump to keep all the various elements particularly calcium and magnesium at the required levels to keep your corals and fish happy.

 

[s_spowart]

You should have taken simple math with the rest of us. Maybe I should have worded it differently. Water changes will reduce pollution but not eliminate it long term. Eventually the pollution levels will climb. They can not be solely relied on.

Funny enough I actually learned this from you in an article you did for Reefkeeping 15-20 years ago. I am going to round out the decimals to make it easier for us simple math people.

If your tank makes 10ppm of nitrate a week, and you do a 10% water change the tank still has 9ppm of nitrate left.

Week two the tank makes 10ppm of nitrate again, but there is still the remaining nine from the week before. So the nitrate is at 19ppm. That 10% water change gets you down to 17ppm.

Week three, tank makes another 10ppm of nitrate, and you had the 17ppm from before for 27ppm. A 10% change gets you down to 24ppm.

Week 4 tank makes another 10ppm of nitrate, add it to the 24ppm that was in the tank puts the tank at 34ppm nitrate. A 10% change brings the tank down to 31ppm

Week 5- tank owner posts on R2R asking why they have algae when their levels are perfect and they do weekly 10% water changes.

This same logic can be applied to using water at NSW levels to dose tanks, but in reverse.

That's why you need an effective nutrient export, a refugium is ideal, and a suitably sized skimmer.
And above all, make sure there is sufficient live rock, and the tank is fully cycled.
Don't simply throw in a full tank of fish on day 1 for example. The bacteria need time to build up to full stocking levels.
You will always have some nitrates, the corals actually use some, but it mustn't be allowed to get too high.
Regular testing should identify if the nitrates are starting to climb, then you need to find the cause of the problem and rectify it.
It's not always easy, but necessary.
Water changes can only do so much, and the more drastically you water change, the more stressed your livestock becomes.
And if a large water change is necessary do it slowly so as not to make too sudden a change to the water parameters.

 

[firechild]

You should have taken simple math with the rest of us. Maybe I should have worded it differently. Water changes will reduce pollution but not eliminate it long term. Eventually the pollution levels will climb. They can not be solely relied on.

Funny enough I actually learned this from you in an article you did for Reefkeeping 15-20 years ago. I am going to round out the decimals to make it easier for us simple math people.

If your tank makes 10ppm of nitrate a week, and you do a 10% water change the tank still has 9ppm of nitrate left.

Week two the tank makes 10ppm of nitrate again, but there is still the remaining nine from the week before. So the nitrate is at 19ppm. That 10% water change gets you down to 17ppm.

Week three, tank makes another 10ppm of nitrate, and you had the 17ppm from before for 27ppm. A 10% change gets you down to 24ppm.

Week 4 tank makes another 10ppm of nitrate, add it to the 24ppm that was in the tank puts the tank at 34ppm nitrate. A 10% change brings the tank down to 31ppm

Week 5- tank owner posts on R2R asking why they have algae when their levels are perfect and they do weekly 10% water changes.

This same logic can be applied to using water at NSW levels to dose tanks, but in reverse.

You're working on the assumption that NO3 production (minus whatever is consumed by the aquarium) is greater than the export. If we take your example and the production minus consumption is 0.5ppm per week, then a 10% water change will initially reduce the NO3 levels until there is equilibrium, which is when NO3 is at around 5ppm, the production will be 0.5ppm and the water change will export 0.5ppm. In your example, there will also be a point of equilibrium but it will be around 100ppm (10ppm production, 10ppm export).

I realise that 5ppm and 100ppm are not the correct numbers because (5ppm + 0.5ppm) - 10% = 4.95ppm but we're working with hypotheticals and I'm not going to get my calculator out.

 

[reefwiser]

The problem you will find is that getting water too clean will cause issues. Like dinoflagellates

 

[Nemosis]

I'm inclined to believe that most of use RODI units to filter (remove unwanted elements) our water before we mix in salts? So in theory, water changes are a form of filtration.

 

[Randy Holmes-Farley]

You should have taken simple math with the rest of us. Maybe I should have worded it differently. Water changes will reduce pollution but not eliminate it long term. Eventually the pollution levels will climb. They can not be solely relied on.

Funny enough I actually learned this from you in an article you did for Reefkeeping 15-20 years ago. I am going to round out the decimals to make it easier for us simple math people.

If your tank makes 10ppm of nitrate a week, and you do a 10% water change the tank still has 9ppm of nitrate left.

Week two the tank makes 10ppm of nitrate again, but there is still the remaining nine from the week before. So the nitrate is at 19ppm. That 10% water change gets you down to 17ppm.

Week three, tank makes another 10ppm of nitrate, and you had the 17ppm from before for 27ppm. A 10% change gets you down to 24ppm.

Week 4 tank makes another 10ppm of nitrate, add it to the 24ppm that was in the tank puts the tank at 34ppm nitrate. A 10% change brings the tank down to 31ppm

Week 5- tank owner posts on R2R asking why they have algae when their levels are perfect and they do weekly 10% water changes.

This same logic can be applied to using water at NSW levels to dose tanks, but in reverse.

I linked the article and a graph from it above.

I certainly agree that there are better ways to control nutrients than water changes, and say so all the time.

I just want folks to know they can make a big difference in nutrient levels, and in some cases are enough to control nitrate, and for some folks with low nutrients, they can be too effective.

 

[Auquanut]

I guess I'll chime in here. Are water changes alone a form of filtration? Technically, no. Removing water and replacing it is dilution, not filtration. If you are vacuuming the sand bed during a water change, yes. Removing detritus through water changes is performing the same function (in a way) as the skimmer and socks. Filtration.

Regardless, if you are achieving results from water changes that supplement your filtration methods, the water changes in all practicality can be considered a part of your filtration method. Just my opinion.

I have an AWC system that changes out about 45 gallons monthly. That's about 1/3 water volume monthly in my 125. I don't do it for nitrate/phosphate control, or to replenish trace elements. I have a very aggressive biological export system and feed pretty heavily. I have a lot of mature coral colonies, so I have to autodose alk and cal to maintain levels, and manually dose trace elements as necessary.

I do it because the way I see it, my reef is in a house. There are a lot of substances that they are exposed to through gas exchange that they never would be exposed to at the same levels on the open reef. If you can smell dinner cooking, there are substances being introduced to the tank that we're not testing for. Most won't even show up on an ICP test. I do run a carbon reactor, but nothing is perfect. It comes back to dilution being the solution to pollution.

So... Is my water change regimen overkill? Don't know. I hope so. Is it not nearly enough? Again, don't know. I hope not. One thing I can say is that it makes me feel more comfortable, and the tank seems to dig it. So, for me, it's worth the investment.

 

[reeftankdude]

For most people, it's more a matter of replacing elements than filtration. I haven't done a WC in 8 months and couldn't be happier (my corals too). Reef Moonshiner here.

what supplements are you using? thanks

 

[stacksoner]

I'm with everyone else, water changes are more of a replacement of elements rather than filtration.

This is like comparing an oil filter on a car to changing one's oil. They serve completely different purposes.

 

[Dav2996]

A water change is normally only needed if something is wrong with your setup.
If you have an effective nutrient export, and replace all the elements needed through dosing then water changes only stress the livestock.
That said, fir a small aquarium it may be necessary to continue changing water as it is harder to get the system stable but for a 100 gallon or larger tank, best have a refugium and suitably sized skimmer, and a good testing regime. Then just use a dosing pump to keep all the various elements particularly calcium and magnesium at the required levels to keep your corals and fish happy.

I have a 20 gallon tank even believe dosing is better. If feel you got to test with 10 test kits make sure the water matches your current water or you got issues. Dosing is sure fire way of no major issues as long as you do it slow.