When to do a water change?

[HH Morant]

I think over-filtration is good. A clean filter is not good.

Over filtration is measured primarily by the effective surface area of your filter media. So a large-capacity filter filled with good media is great. I am in the process of converting my canister filters to 30 ppi  poret foam (ppi is pores per inch), which I am convinced is the best filter media. I have not completed the process, but 5 weeks (about 50%) into the conversion I can already see that my water is clearer, even though I now have no mechanical filtration (you have to go to 40 ppi foam to get much mechanical filtration).

Cleaning your filter is not good. Although I have opened my canister filters in the last 2 months to take some of the old media out and replace it with foam, I have not cleaned the filters. The gunk in your filter is home to much beneficial bacteria, and when you take it out of your filter you do harm. Cleaning the filter is necessary only to maintain flow. If you can maintain flow by just opening the canister and replacing the mechanical filtration - without cleaning the rest of the media or the filter - that is better.

There are a series of articles about filtration and filter media at aquariumscience.org which convinced me to take the path I am taking with filtration. The author of the site has little patience with those who disagree. I will call this tendency "DIT" (Dave's Intemperate Tone). This puts some people off. But I think the ideas in the filtration articles are sound, so I don't let DIT dissuade me from benefitting from them.

[KentFishFanUK]

On 7/24/2021 at 6:24 PM, laritheloud said:

I don't have any fact-based reasoning to back up what I do, but I change all my tanks at around 30 to 50% every week, including wiping down the inside and outside of the glass and rinsing/cleaning my filters. The fish always seem to perk up with a water change and it often triggers spawning behaviors in my tetra. I like to create a habit/routine and stick with it.

Caveat: I do have a legit OCD diagnosis, and a set routine and predictability is very helpful in maintaining my tanks without caving in to an impulse of overdoing it. So this is what works for me.

In a sense do 'what works for you" is the most accurate answer anyone can really give right? Even if its not so specific haha

[KentFishFanUK]

On 7/24/2021 at 6:37 PM, HH Morant said:

I think over-filtration is good. A clean filter is not good.

Over filtration is measured primarily by the effective surface area of your filter media. So a large-capacity filter filled with good media is great. I am in the process of converting my canister filters to 30 ppi  poret foam (ppi is pores per inch), which I am convinced is the best filter media. I have not completed the process, but 5 weeks (about 50%) into the conversion I can already see that my water is clearer, even though I now have no mechanical filtration (you have to go to 40 ppi foam to get much mechanical filtration).

Cleaning your filter is not good. Although I have opened my canister filters in the last 2 months to take some of the old media out and replace it with foam, I have not cleaned the filters. The gunk in your filter is home to much beneficial bacteria, and when you take it out of your filter you do harm. Cleaning the filter is necessary only to maintain flow. If you can maintain flow by just opening the canister and replacing the mechanical filtration - without cleaning the rest of the media or the filter - that is better.

There are a series of articles about filtration and filter media at aquariumscience.org which convinced me to take the path I am taking with filtration. The author of the site has little patience with those who disagree. I will call this tendency "DIT" (Dave's Intemperate Tone). This puts some people off. But I think the ideas in the filtration articles are sound, so I don't let DIT dissuade me from benefitting from them.

Yeah when I 'clean' my filter I just shake out the sludge from the foam so the water flow goes back to normal, I don't touch the seachem matrix or biohome filter medias in there at all. I'm hoping that a good chunk of the nitrifying bacteria is in the media and not the sponge, so if/when I change the filter or even upgrade tank etc I can just move the bag of media to the new filter and it's ready. 

[OnlyGenusCaps]

On 7/24/2021 at 10:49 AM, MJV Aquatics said:

I tend to believe (but of course can't prove) that nitrates in source water is not as harmful as tank generated nitrates.

On 7/24/2021 at 10:53 AM, HH Morant said:

My nitrates are often in the 40-80 range, and I do not believe that hurts the fish. I sometimes do 67% water changes every 2 weeks, sometimes every three weeks. I change the water in my mom's aquarium when I visit her (she cannot do it), which is every couple of months or so. The nitrate levels in her aquarium are often over 100 ppm, but her fish are fine.

On 7/24/2021 at 10:49 AM, MJV Aquatics said:

Perhaps because tank generated nitrates also contain many other pollutants we simply can't measure.

I realize I sort of split of the quotes here, but it was in hopes of making a point.  I see this sort of combination of comments often (frequently in far less civil discussions of the topic).  I don't know that there is enough hard data to support or refute either of the possibilities that these sorts of observations suggest. 

One possibility is that the chemical nitrate species coming from ground water are different from those being generated in a tank.  That, given funding, seems like it would be pretty straightforward to determine. 

The other possibility would be the suggestion that nitrates tend to be associated with something, as yet unidentified, that is causing harm to the inhabitants of the tank.  In this case the nitrates themselves are not the primary culprits.  However, this could be a noisy correlation and therefore nitrates may often, but not always, be good predictors of stress to the inhabitants.  This would be far more challenging to conclusively study particularly if the associated compounds are not known.  Though it might be possible to demonstrate that the nitrates are not inducing stress as previously believed.

To be clear, I am not arguing that water changes are bad.  Simply that the above patterns seem to be observed often and suggest there is likely more complexity than we yet understand. 

[KentFishFanUK]

On 7/24/2021 at 6:44 PM, OnlyGenusCaps said:

I realize I sort of split of the quotes here, but it was in hopes of making a point.  I see this sort of combination of comments often (frequently in far less civil discussions of the topic).  I don't know that there is enough hard data to support or refute either of the possibilities that these sorts of observations suggest. 

One possibility is that the chemical nitrate species coming from ground water are different from those being generated in a tank.  That, given funding, seems like it would be pretty straightforward to determine. 

The other possibility would be the suggestion that nitrates tend to be associated with something, as yet unidentified, that is causing harm to the inhabitants of the tank.  In this case the nitrates themselves are not the primary culprits.  However, this could be a noisy correlation and therefore nitrates may often, but not always, be good predictors of stress to the inhabitants.  This would be far more challenging to conclusively study particularly if the associated compounds are not known.  Though it might be possible to demonstrate that the nitrates are not inducing stress as previously believed.

To be clear, I am not arguing that water changes are bad.  Simply that the above patterns seem to be observed often and suggest there is likely more complexity than we yet understand. 

Well volunteered let us know what you determine 😉 haha.

To be honest I'm surprised those studies haven't been done in a university or something, it must have implications further than just the hobby right? Unless I'm missing something obvious, I'm not very scientifically literate. 

 

[HH Morant]

On 7/24/2021 at 12:44 PM, OnlyGenusCaps said:

I see this sort of combination of comments often (frequently in far less civil discussions of the topic). 

I agree. I appreciate the civility and courtesy of the folks in this community. 

[Jefft51]

Nitrate and nitrite are non organic compounds and are ions. Nitrate is NO3- and Nitrite is NO2-.   As such, these won't differ from well water or biological creation. However they can combine to give things like potassium nitrate or sodium nitrate (mmm bacon). I don't know how the tests for the ions work so not sure if you can get differing results with bound up nitrates/nitrites.  So, if the tests are accurate for only the ions and you're seeing differing results as far as fish health, then it's something else (not tested?) If the tests are picking up bound nitrates then you would be getting a false high reading. If the bound nitrate compound is detrimental is another issue.  So my conclusion is maybe.

As a side note Ammonia is NH3.

As far as fish surviving in high concentrations of Nitrates, sort of depends on the fish. Some are more sensitive and others more hardy. However the high concentrations might not kill the fish, it will stress them and make them susceptible to other things. 

Also I'm drawing on my chemistry classes from a looong time ago so take that with a grain of NaCl.

[Hobbit]

On 7/24/2021 at 1:37 PM, HH Morant said:

The gunk in your filter is home to much beneficial bacteria, and when you take it out of your filter you do harm.

In my case, I have a heavily planted tank with driftwood and a soil substrate. I’m definitely losing beneficial bacteria when I squeeze out the filter, but I have soooooooo much more bb in the rest of the tank and such a small bio load that it doesn’t matter. In fact I designed the tank to not need a filter at all—the only reason I added it was for mechanical filtration. I realize this isn’t the case for many fish keepers though. I ended up with sort of a weird tank.

On 7/24/2021 at 1:37 PM, HH Morant said:

There are a series of articles about filtration and filter media at aquariumscience.org which convinced me to take the path I am taking with filtration.

It looks like this site is in favor (or at least okay with) cleaning well established filters because the biofilm will be tough enough to survive washing. Yay! 😄

It’s so hard to speak in generalities about these topics because everyone’s setup is so different.

On 7/24/2021 at 2:42 PM, Jefft51 said:

As such, these won't differ from well water or biological creation. However they can combine to give things like potassium nitrate or sodium nitrate (mmm bacon). I don't know how the tests for the ions work so not sure if you can get differing results with bound up nitrates/nitrites.  So, if the tests are accurate for only the ions and you're seeing differing results as far as fish health, then it's something else (not tested?) If the tests are picking up bound nitrates then you would be getting a false high reading. If the bound nitrate compound is detrimental is another issue.  So my conclusion is maybe.

I think another possibility is that nitrates (such as those from commercial fertilizer) come along with other compounds—not necessarily bound together, but just dissolved in the same solution—that could be harmful to fish.

[Scott P.]

On 7/24/2021 at 1:37 PM, HH Morant said:

I think over-filtration is good. A clean filter is not good.

There are a series of articles about filtration and filter media at aquariumscience.org which convinced me to take the path I am taking with filtration. The author of the site has little patience with those who disagree. I will call this tendency "DIT" (Dave's Intemperate Tone). This puts some people off. But I think the ideas in the filtration articles are sound, so I don't let DIT dissuade me from benefitting from them.

Some really good reading at that website.

[Wonder Boy]

+1 for @Irene’s video. Very helpful. 

We are trying to plant our 56 gallon to the point we do the bare minimum water changes. Love getting my hands wet, but water changes are no fun. 

[MJV Aquatics]

On 7/24/2021 at 1:37 PM, HH Morant said:

I think over-filtration is good. A clean filter is not good.

Over filtration is measured primarily by the effective surface area of your filter media. So a large-capacity filter filled with good media is great.

I tend to agree. Ideally it would be nice to remove organic waste before it can decompose and pollute the aquarium water. But this is practically impossible unless you cleaned the filter media daily...and this would be counter-productive from a bio-filtration perspective. A better approach is to minimize organic waste inputs by feeding less and removing plant waste.

I'd also like to restate or clarify a previous statement. When I posted that tank generated nitrates are perhaps worse than nitrates from source water, I did not mean that the nitrates themselves were really any different. Merely that tank generated nitrates are also in combination with other pollutants resulting form decomposition that don't necessarily make the trip in source water 'contaminated' by agricultural run off of chemical ferts.

Edit: I would tend to disagree about over filtration, or rather the conventional thinking about over filtration. To many hobbyists, over filtration is additional or more powerful filters up to 10x flow relative to tank volume. Over filtration in terms of increased filtration surface area is another matter although overkill can be pointless.

Edited August 18, 2021 by MJV Aquatics

[Streetwise]

I want my organic waste to rejoin the substrate and help feed the plants. I don’t see it as pollution. However, I am running organic soil tanks where decomposition is part of the formula.

[Hobbit]

@MJV Aquatics I was thinking of you the other day when I watched one of @Zenzo’s recent videos about how he gets his fish to grow so big. One of his answers was lots of water changes. 👍

[MJV Aquatics]

On 8/18/2021 at 8:58 PM, Hobbit said:

@MJV Aquatics I was thinking of you the other day when I watched one of @Zenzo’s recent videos about how he gets his fish to grow so big. One of his answers was lots of water changes. 👍

There are different schools of thought... Greg Sage of Select Aquatics, my friend and collaborator (I have many of his articles on my blog) swears by super fresh water to grow out larger fish quicker. Auto water changing and large capacity tanks w/sumps. On the other hand, Charles Clapsaddle of Goliad farms has vats in his greenhouses on a closed system, lots of plants, and doesn't do water changes. His vats has several inches of mulm that he's convinced is beneficial, full of beneficial bacteria and paramecium.

I think both methods clearly can work as it does for them as long as the water quality remains high. For the average hobbyist, I think there's no such thing as too much fresh, clean water...but there also needs to be sufficient aeration/filtration to leverage beneficial micro-organisms.

[Tom H]

I only change when needed, unless I'm raising fry.

[Zenzo]

On 8/18/2021 at 7:25 PM, MJV Aquatics said:

There are different schools of thought... Greg Sage of Select Aquatics, my friend and collaborator (I have many of his articles on my blog) swears by super fresh water to grow out larger fish quicker. Auto water changing and large capacity tanks w/sumps. On the other hand, Charles Clapsaddle of Goliad farms has vats in his greenhouses on a closed system, lots of plants, and doesn't do water changes. His vats has several inches of mulm that he's convinced is beneficial, full of beneficial bacteria and paramecium.

I think both methods clearly can work as it does for them as long as the water quality remains high. For the average hobbyist, I think there's no such thing as too much fresh, clean water...but there also needs to be sufficient aeration/filtration to leverage beneficial micro-organisms.

I think the difference with Charles, is that their system at Goliad is so large, with giant plants and trees growing up to the ceiling of their greenhouses, that water changes may not be nearly as necessary as the common hobbyist keeping fish in systems a fraction of the size. 

[MJV Aquatics]

On 8/19/2021 at 2:05 PM, Zenzo said:

I think the difference with Charles, is that their system at Goliad is so large, with giant plants and trees growing up to the ceiling of their greenhouses, that water changes may not be nearly as necessary as the common hobbyist keeping fish in systems a fraction of the size. 

Of course, but one could make the case that the principal could be scaled down to the home aquarium in that with enough fast growing plants that convert nutrients (aka pollution) into plant tissue, partial water changes, be it frequency and/or volume, could be far less than a similar tank with only plastic decor (Assuming good aeration/filtration and appropriate bio-load for balance).

On the other hand, there's rarely, if ever, been a case that I've heard of where too much fresh, clean water caused a problem.

Edited August 19, 2021 by MJV Aquatics

[Zenzo]

On 8/19/2021 at 12:32 PM, MJV Aquatics said:

Of course, but one could make the case that the principal could be scaled down to the home aquarium in that with enough fast growing plants that convert nutrients (aka pollution) into plant tissue, partial water changes, be it frequency and/or volume, could be far less than a similar tank with only plastic decor (Assuming good aeration/filtration and appropriate bio-load for balance).

On the other hand, there's rarely, if ever, been a case that I've heard of where too much fresh, clean water caused a problem.

Very true. I have both seen and personally have had heavily planted tanks with a minimal bio load that could go a long time without elevated nitrate levels. That's also why I try to have plants in every freshwater tank, even my cichlid tanks that can destroy plants (pothos or hornwort seems to do ok). 

[Nik_n]

I have a 50gallon planted tank. I usually do water changes every 2-3 weeks. This summer I was gone for 2 moths. I left the auto-feeder on and did a 60% water change before I left. When I came back, about two months later I tested the water and it showed that NO2, NO3 and ammonia were all zero. To be fair I only had 5 fish in the tank with 5 amazon swords and many other plants, so it wasn't a big problem for me. 

I'm sure it has already been said but I will say it again as I found it to be true: The frequency of water changes depends on three things. 1. If the tank is cycled properly 2. The amount of live plants 3. Stocking levels. But it really comes down to plants. The more plants you have the more "filters" have. Plants act as filters in the wild. That is way ecosystem and non filter tank works. 

Basically what I'm saying is that the amount of water changes needed varies from tank to tank. Different tanks have different inhabitants, are different ecosystems and require different amounts of care.  

 

[MJV Aquatics]

On 8/19/2021 at 3:46 PM, Nik_n said:

But it really comes down to plants. The more plants you have the more "filters" have. Plants act as filters in the wild. That is way ecosystem and non filter tank works. 

But if we're comparing tanks to nature we'd have to acknowledge that in nature, fresh water is constantly renewed by rain and snow melt. Creeks, streams, and rivers flow endlessly. I read that the volume of water exiting the amazon river is so great that fresh water can be collected 12 miles out at sea. Ever go to Niagara Falls and marvel at the millions of gallons flowing between the Great Lakes?

So nature does water changes 24/7 in a flow through system! Now of course there are exceptions, but the water quality is typically much lower in those exceptions.

[Nik_n]

On 8/19/2021 at 10:48 PM, MJV Aquatics said:

But if we're comparing tanks to nature we'd have to acknowledge that in nature, fresh water is constantly renewed by rain and snow melt. Creeks, streams, and rivers flow endlessly. I read that the volume of water exiting the amazon river is so great that fresh water can be collected 12 miles out at sea. Ever go to Niagara Falls and marvel at the millions of gallons flowing between the Great Lakes?

So nature does water changes 24/7 in a flow through system! Now of course there are exceptions, but the water quality is typically much lower in those exceptions.

Yes of course. Thats completely true. All I meant to say is the importance of plants and the way they affect water quality and how they tie in with the frequency of water changes.