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Is Biofilter Removal Possible?

5K views 46 replies 14 participants last post by  Deanna 
#1 ·
In a well-planted high-tech tank (maybe 50-60% of the substrate planted) with thriving plants and a heavy fish load, is it possible to remove the bio-filter so that the plants no longer compete with the bacteria for ammonia? I assume that the nitrifying bacteria in the tank (substrate, plant surfaces, etc) would not be able expand to take up the load. I would remove the media gradually and watch ammonia levels carefully. If the plants can’t quite keep up, perhaps it’s possibly to find a minimal media amount?

Strong circulation (via Koralia pumps) and mechanical filtration would continue. I’m thinking that I could gradually reduce the media in tandem with a gradual reduction in nitrates while carefully monitoring plant health to be sure nitrogen is not limited. EI dosing and water changes would continue, but with a gradually reduced nitrogen component.

Has anyone tried this?
 
#3 ·
I too am curious as to how much nitrifying bacteria is actually in my bio media with a heavy planted tank. Because you will only ever have the amount of BB that is required for the tank. You could always have a ton of media but only so much will actually house BB depending on load and such. Am I right?


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#5 ·
The part that leaps out at me is the 'heavy fish load' part of the equation. Everybody defines this differently, so what kind of fish are being kept and how many?

Beyond that, I've got nothing to add. I like my filters. I don't see crud of any form hanging around and the fish always look they're swimming in air without the use of Purigen and all of that.
 
#6 ·
Part of it might be how we define bio-media as what we call mechanical also does a fair amount of bio. We don't think of the walls as a bio filter media but we do know it works. That leaves me thinking that slowly/ carefully removing/ reducing the stuff we do call bio is okay. If we can get more flow with the same filter just stuffed with mechanical, that would seem to be some benefit. There are not going to be too many that have worked it from that angle but then there are a number of folks who do change out media that is normally thought of as bio and replace it with mechanical. Possibly just not thinking of it in the same terms?
Sounds like an interesting idea to see how far it could be pressed.
 
#7 · (Edited)
I have about 35 small to medium tropical fish plus one large (3") gourami and 6 amanos in a 29 gallon tank - about double what I should have. All healthy and enough to generate a persistent 10-20 ppm nitrate level (calibrated nitrate test). That will be the challenge, requiring close monitoring.

The bio-filter I'm referring to is the long-standing Matrix. Mechanical is the micro filtration pad in a canister.
 
#10 ·
@Smooch I think the idea is to push boundaries and get a better understanding of how much extra bio filtration is needed, if at all. Strictly for learning purposes not as an actual recommended setup. I have to say if she is willing to put in the effort succeed or fail I admire the willingness to do so and share the findings.
It's all good.

I understand that not everybody treats their fish the same way I treat mine. I openly admit to being a 'hover fish parent' even though logically I know I cannot protect them from everything. I'm the same way with all of our other pets. Birds, dog, rabbit, tortoises and to a extent, the wild critters outside. I'm sure the grumpy groundhog that lives in the backyard would have plenty to say if he could. This is how I roll. If people want to judge me for that, I don't care.

There have been people around here that have done these kinds of things in the name of just to get attention and it got ugly. I do not think that is the intention here, but I still think a backup plan is a good idea. Just because I think something is a good idea doesn't make it so.
 
#12 ·
Maybe have a standby cycling tank with extra bio media in it ensuring there is ammonia to keep the cycle going in case things do go bad and can always put the cycled media in. I always have an extra filter between my two tanks going just in case.


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#13 · (Edited)
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#17 ·
I agree with @Smooch on it being a good idea to have a backup; if things go wrong and you don't have a filter anymore, you could lose all your fish, which, aside from the ethics of it, would be a huge financial blow. Prime is useful, but won't save your butt long-term. I'd probably keep the filter running on a bucket or empty tank that you feed daily with ammonia, at least until you're sure your tank is safe without a filter.
 
#18 ·
OP is going to do what OP is going to do.

My thoughts on this are not about the financial side of it. It is about being humane. Damage done to fish via high amounts of ammonia is not something that can be repaired. I've dealt with this myself, although it wasn't because I wanted to experiment, push limits or see if my curiosity was in line with facts or if things that are said are works of fiction.

I'm not a fan of the Walstad method. The rules as it were are often twisted in every which direction to accommodate which ever way the wind is blowing on any given day. Just reading the preview from her new book suggests that people may not be able to grow plants due to the lack of soil. Seriously? I don't mind my weekly 20-minute tank maintenance. It is one thing I actually look forward to as I find it therapeutic. She recommends small fish with low stocking. https://dianawalstad.files.wordpress.com/2017/04/epa_preview.pdf I at least agree with the low stocking part of it. Both of my tanks are low stocked by choice. Do I consider a heavily stocked 29 gallon lightly stocked? No.

Yes it is true that BB lives all over a tank. It is also true that plants work as 'filters'. Do I think plants are a fix all in a planted tank? No. Don't get me wrong, I love plants. I surround myself with them inside and out, but I don't think they are cures for laziness and other things people do in this hobby.

As I said previously, this is not like some of the other experiments done around here. Case in point: Filling a tank with fish with uncycled Aqua Soil, in a uncycled tank with no filters or water changes is and was a bad idea. It killed everything in the tank and turned out to be a total flop.

Things are being monitored in this situation, so I wish OP the best of luck.
 
#19 ·
Maybe we could get the OP to tell us more about what prompts them to ask the question?
I can see some value in just knowing as it is something that we might all learn more about. I could also see some value if one is using the Seachem Matrix. If we are using an extra product, it would be nice to see a way without that extra. That might lead to a different, possibly better, way of dealing with the nitrate.
Can I ask how the OP came to be using the Matrix? I've seen it but never got involved in using it. Am I missing something about the product that I should know?
 
#20 ·
I've never used a specific "biomedia" in any of my tanks and none of the fish have ever been the wiser. I will fill my Eheim 2026 with nothing but floss and then I change out one basket each time I clean the filter - usually once a month. I have absolutely no doubt that the filter floss is filled with plenty of BB. I've done it this way with both heavily and lightly planted and stocked tanks and have found it works exceptionally well regardless of having no "biomedia". To boil it all down what I'm getting at is remove the "biomedia" if you like. If you feel better testing for ammonia then do it. I doubt you'll see an appreciable (or detectable) increase in ammonia or nitrite.
 
#21 ·
Most of my filter is now filled with sponge (the rest is a bit of ceramic rings and purigen). What's worse - I'm cleaning the sponges in tap water! Same for internal filter. Ok, my tap doesn't contain any chlorine, but still. Really, heavily planted tank with deep substrate is a biofilter on it's own. For few days I was left without my biofilter (valve broken), only problem I had was no CO2 (inline diffuser), parameters didn't go off.
 
#23 · (Edited)
Maybe we could get the OP to tell us more about what prompts them to ask the question?
It’s not about eliminating the biofilter. It’s about providing as much NH4 as the plants will take up, rather than relying mainly upon NO3. The ultimate goal is to find out if there will be a noticeable difference in plant health without harming the fish.

Since plants seem to prefer NH4 to NO3, I was thinking; why not let the plants eat before the BB without having to add ammonium as a supplement? I suspect, in the end, that I will just find a greatly reduced (optimized?) level of bio media. Right now, I fill the filter basket with Matrix figuring the more the better. Now, I’m wondering if less (maybe none) is better by providing only enough nitrifying media to keep NO3 at a very low level, which, in my case, would be less than 5 ppm. I know that NO3 levels in the 20-40 ppm are harmless, but it says to me that all that ammonia is being used unproductively from a plant perspective.

At my pH levels of 6.0-7.0 (CO2 day/night variability), the NH3 should almost instantly be converted to NH4. So, while I’m not too concerned about NH3 or NO2 spikes (which I will still monitor), I am concerned about determining if unlimited nitrogen is being sustained. I’d rather not wait for deficiencies to develop, which could cause a downward cascade by that time. So, I’m going to watch for changes in phosphates (now in the 5 ppm area) assuming that a drift higher means plants are limited by something (nitrogen in this case) or assuming that a drift lower means plants are becoming healthier and the non-nitrogen nutrients are becoming limited. That, when combined with total ammonia testing (while trying to keep free ammonia near zero), may help show me the point of balance.

Things to watch (I’m sure ither thoughts will pop-up along the way):
- When photyosynthesis stops at night, will it create a problem
- Will the tank be more/less prone to algae.

Who knows where this is going to end, but I have plenty of Prime and zeolite on hand that could be employed while I rebuild the BB colony, if needed.

Can I ask how the OP came to be using the Matrix?
I selected Matrix as the bio-filter media simply because it is renown for being a high-quality porous media. I’ve been using it for about 15 years, maybe more.

The above three posts give me added confidence that I can remove most, if not all, filter media and may actually have answered my initial question.

I do have a question for the three of you: do you have total ammonia (not free ammonia) testing levels above zero? That might indicate that the ammonium that plants like is being made available.
 
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#27 ·
Now, I’m wondering if less (maybe none) is better by providing only enough nitrifying media to keep NO3 at a very low level, which, in my case, would be less than 5 ppm. I know that NO3 levels in the 20-40 ppm are harmless, but it says to me that all that ammonia is being used unproductively from a plant perspective.
The ammonia/nitrate (when converted) is only being used umproductively because of your EI dosing of N. Nothing to do with filtration in that aspect. I think you could probably start dropping N dosing due to your stock, but you would have to test to make sure you stay in good ranges. Also, I don't feel it can improve plant health that much by them only taking up NH4+, these things are also hard to quantify, but by all means you should have a go to see if you find a difference. From how I see it nitrate and ammonia are just means to end that the plants need, they need the nitrogen atoms for protein synthesis yadda yadda. NH4+ may be preferred for a transport reason (admittedly I don't know if someone could say exactly why it's preferred that would be good), but if NO3- is sufficient I don't think it makes a difference.
Again, I am in agreeance with you on the other aspect of your question, that maybe commercial bio media isn't as important as we think it is and sponges and all do the job fine. I would consider sponges bio media as well to an extent, but just to make the distinction I think it's important to state, bio-media most of us are referring to through this discussion is ceramic commercial stuff.


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#24 · (Edited)
Low PH being the key here so I'm just going to throw this out here. Have you thought about lowering your Co2 output and run constant 24hr to keep PH closer to 6 all the time? with your photo periods broken up into blocks of 4 hrs or so? This would allow Co2 concentrations to replenish in between photo periods and not let them build up to toxic levels while keeping a more stable PH at a lower level thus keeping more nitrogen in ammonium form rather than converting back to ammonia over night.

Just a thought

Added: I don't read any NH3/NH4 but at a PH of say 6 and a temp of 25C, 35ppm reading of total ammonia would equate to 0.019901ppm free ammonia. So I think the key to your testing will be a very stable low PH which is by some considered safe levels.

Dan
 
#25 · (Edited)
That probably would give a more stable testing environment, but I've tried the "siesta" concept with 4-hour photoperiods, along with adjusted CO2 for pH stabilization, before (for other reasons) and found that plants don't do quite as well and that algae gained a slightly better foothold. I'm not too concerned about the nighttime. It's just something I'm going to watch. Since my pH doesn't get above ~7.0, NH3 shouldn't become a problem.

Based upon the discussions, above, I'm starting to think that the BB in substrates and intra-tank surfaces is capable of doing most of the nitrifying work, at least enough to provide a safety net. Of course, in my case, the heavy fish load is cause for increased monitoring during my upcoming trial.
 
#26 ·
Now you have me thinking since I think I wasn't exactly clear on your goals to begin with. You may want a substrate with a high buffering capacity to lower your PH as close to 6 as possible and you would want a KH of 1 or less (I'm thinking ADA Amazonia) and possibly add additional products natural or synthetic to further buffer PH this will be a safety net incase Co2 fails as that would be absolutely catastrophic. But I think the real challenge will be trying to prevent the growth of BB from converting it to nitrate.

Dan

Bump: Trying to find a buffering substrate that is not as ideal for BB as Amazonia might be worth it in that fight removing filter media and maybe replace with peatmoss bags? adding drift wood I'm having a hard time thinking of things that don't contain tannins and are not a chemical $$$ sink.

Dan

Bump:

Safe levels of total ammonia with a PH of 7 at 25C are only about 3.5ppm. There is a huge difference in 1 ph change so 3.5 would be your max if you let your PH return to 7 at night.

Dan
 
#29 ·
I'm going to be a contrarian here and say biofiltration capacity is essential to planted tanks, especially high tech ones. ADA knows this and you should too.

Most folks miss the point. Ammonia, nitrite, nitrate are not the only waste products of concern that microbes process. There are many other types of wastes, collectively known as dissolved organic compounds (DOCs), that are not measured by standard test kits but also play a huge role in the health of your plants, fish, and tank. The biofilter also processes these, while plants may not necessarily do so (in fact plants can be huge producers of organic wastes, especially if unhealthy). These compounds are what make your tank look dirty and prone to algae (especially bba).

Gather round, it's story time. Once upon a time, I had a 120 gallon high tech tank. No matter how much I tried to remove detritus at the weekly water change, the tank always had a huge buildup of loose mulm around the bottom. I eventually bleached it because the bba was horrendous and the plants past the point of saving. In this tank I only have one Eheim 2217, which I thought would be adequate because it was rated for tanks up to 164 gallons.

Soon after, I redid the tank. In my research, I found that it was very likely only one 2217 wasn't sufficient for a tank my size (based on others' experiences) so I purchased another. Now there are certainly many other factors at play (improved systems design, focus on microbial balance, etc.), but the tank has been much cleaner. Almost no detritus to suck up at water changes, and even when many plants are not doing well there isn't much visible (without siphoning it out you'd never know).

Some months ago, I was playing around with lily pipes and various outflows, and forgot to plug one of the filters back in. I noticed after a couple of the days when the tank got cloudy. This is unusual, as by conventional standards my bioload should be quite low with only a few Otocinclus and several dozen shrimp. However I noticed quite a stark difference, which went away a few days after plugging back in the second filter. This goes to show that even in lightly stocked tanks, where there's little ammonia/nitrate being produced, biofiltration still has a huge impact.
 
#30 ·
I'm going to be a contrarian here and say biofiltration capacity is essential to planted tanks, especially high tech ones. ADA knows this and you should too.

Going to try to explain this away for the sake of argument.

Most folks miss the point. Ammonia, nitrite, nitrate are not the only waste products of concern that microbes process. There are many other types of wastes, collectively known as dissolved organic compounds (DOCs), that are not measured by standard test kits but also play a huge role in the health of your plants, fish, and tank. The biofilter also processes these, while plants may not necessarily do so (in fact plants can be huge producers of organic wastes, especially if unhealthy). These compounds are what make your tank look dirty and prone to algae (especially bba).

I don't think there is a way to completely eliminate BB its on the glass, in the substrate, on ornaments, plants etc. not just the biomedia. But the attempt here is to reduce the amount of BB so it will limit its effect on the conversion of ammonia to nitrates. This may well leave enough BB for all those DOC's or may not but without testing we have no idea.

Gather round, it's story time. Once upon a time, I had a 120 gallon high tech tank. No matter how much I tried to remove detritus at the weekly water change, the tank always had a huge buildup of loose mulm around the bottom. I eventually bleached it because the bba was horrendous and the plants past the point of saving. In this tank I only have one Eheim 2217, which I thought would be adequate because it was rated for tanks up to 164 gallons.

Soon after, I redid the tank. In my research, I found that it was very likely only one 2217 wasn't sufficient for a tank my size (based on others' experiences) so I purchased another. Now there are certainly many other factors at play (improved systems design, focus on microbial balance, etc.), but the tank has been much cleaner. Almost no detritus to suck up at water changes, and even when many plants are not doing well there isn't much visible (without siphoning it out you'd never know).

The added filter kept the detritus from settling on the bottom allowing it to be sucked up into the filter for manual removal later. I would say the reduction in detritus would most likely be do to increased flow keeping it suspended until it was removed by the filter and was a result of increased flow not added filtration. This could be achieved by adding a powerhead as the OP suggested in doing.


Some months ago, I was playing around with lily pipes and various outflows, and forgot to plug one of the filters back in. I noticed after a couple of the days when the tank got cloudy. This is unusual, as by conventional standards my bioload should be quite low with only a few Otocinclus and several dozen shrimp. However I noticed quite a stark difference, which went away a few days after plugging back in the second filter. This goes to show that even in lightly stocked tanks, where there's little ammonia/nitrate being produced, biofiltration still has a huge impact.

I would disagree that this shows biomedia is needed in a filter. BB is everwhere in the tank and will grow to the needs of the tank provided it has enough surface area and I would think plenty in the tank for the stocking you have The results you were seeing was likely due to the change in flow, mechanical filtration etc. and cutting off a portion of the BB forcing it to multiply elsewhere to catch up. removing half the substrate could have the same effect as removing one filter if you didn't take into account mechanical filtration and flow etc.
My thoughts on arguments that could be made against.

Dan
 
#31 ·
Thanks for sharing your thoughts. It's far from a controlled experiment for sure, but this has been my experience.

But since you bring up flow: the tank with only one filter and a lot of detritus actually had substantially more flow! Back then I was drank the Kool-Aid of super high turnover and surface agitation. I ended up finding my plants did better not getting blasted around so in the tank with two filters I have no additional circulation, which ends up being much less flow than 1 filter + ~2000 gph of powerheads.

But what I want folks to consider is that not just animals contribute and produce organic wastes. Plants (especially unhealthy ones) will as well.
 
#32 ·
Most folks miss the point. Ammonia, nitrite, nitrate are not the only waste products of concern that microbes process. There are many other types of wastes, collectively known as dissolved organic compounds (DOCs), that are not measured by standard test kits but also play a huge role in the health of your plants, fish, and tank.
Do the two forms of BB truly process any wastes other than ammonia and nitrite? Can you cite any studies on that? I’d be interested. However, your point about other organic waste might demand the use of something such as Purigen which, I think now, I’ll throw back in the filter as I reduce the bio-media (took out 1/3 this week). Another issue is pH. With the CO2, I find that my pH drops from above 7 down to the 6.2-6.4 area during the day (kH is in the 5 degree area). That is supposed to severely inhibit any nitrification by the BB, yet no ammonia spikes. Next week, I drop to ½ of the current bio-media.
 
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#36 ·
Don't get me wrong though I definitely feel there is no harm in more filtration and provides a bigger safety net but you only need enough BB to accommodate for your bioload and anything beyond is not utilized.
Dan: you had some interest in this, so I thought I'd update on my progress. It's been slow, as I have wanted to avoid causing a crash. I am now at ~30% of the bio-filter that I once had (Matrix). I am now at Seachem's minimum recommendation of 130 ml for 26 US gallons (29 g tank), which tells you that I had a great deal of overkill on the bio-filter side.

So far, flora and fauna are healthy. No NH3 or NO2, but NO3 remains in the 25 ppm area (50% weekly WC). I suspect that the plants have increased their use of the NH3/NH4, leaving much of the NO3 alone, and that the substrate has grown a larger bio-base.

Will update in the future once I get to zero bio-media in the filter (GASP!).
 
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#40 ·
Well it is over exaggerated when it comes to biofiltration in planted tank (or other decorated tank with substrate, driftwood, stones). For a long time I've been cleaning my media in tap water, even so called biomedia, we don't have chlorine here in Poland though. In bare bottom tanks filter is the only carrier of bacteria. I know we all have planted tanks, but let's not generalize ;-)

Another thing to remember is water flow and mechanical filtration. Basically with planted tank we can toss canisters, sumps etc., but to get crystal clear water we need high flow and big mechanical filtration, if we don't want it in the tank... well, we're back to canisters and sumps. So it's good to know that when we change the filter for a new one we can do it instantly, or when we clean the filter media we can do it in the tap water (be careful with chlorine), but we won't get rid of our filters ;-)
 
#43 ·
Keep in mind that sponges used for mechanical filtration still has BB, as does all surfaces inside your canister and tubing.

While we do tend to overfilter, there is no getting around the fact that if you aren't mechanically filtering out things under a certain size, you are going to see that stuff float around in the tank. Your water will still look crystal clear, but it will still have stuff floating in it (whether your eyes can see and know it or not).

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