# Problem in low-tech tank with decay and bba



## jake21 (Aug 11, 2019)

I have two 29 side by side and one (both low tech); both have the same hardware with the primary difference in fish population and substrate. One can grow plants quite successfully and has little problem with decay or adverse algae such as bba (the black one); the other has frequently problem with decay esp in floating plants, brown smudge stuff and areas of bba. I've been assuming this is due to the substrate in some fashion as the white one does get some compression and some sulfur gas build-up and have been contemplating as an experiment tearing it down and replacing the substrate with the same stuff in the 'good' tank. The black substrate is slightly coarser and 'waste' tends to settle on top my only tiny reluctant in replacement (other than work) is that the apisto and kuhli likes digging in the white stuff (the white stuff is caribsea moonlight which from their website is quite powdery fine - the black substrate is estes stoney river and they email me the grain size and it is a bit coarser but not huge but in working with both tanks over the past 18 months it has a different behavior in how stuff like waste mixes in it (it mostly settles on the surface for example). This is not a new problem and has been on going for over a year (the white tank actually broke and i had to replace the tank but same equipment and substrate went back in and the issue picked right where it left off after the replacement. 

Examples of some of the difference is that in the black tank hornworth grows very cleaning and quite nicely while in the white tank it becomes a brown smudge over time and eventually has to be removed and toss. The frogbit in the white tank develops a brown smudge in the roots and has a bit of a foul smell while in the black tank they stay crystal clean and without issue.

I'm presuming the issue is with the substrate but perhaps it is some other issue I simply do not understand hence this post:

(I do 50% water change on this two tanks twice a week over the past 18 months)


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## Broseff (Mar 14, 2021)

Maybe it's the wood? I had a tank that was having similar problems. I eventually took the wood out, replaced with a different piece of wood and now I don't have any issue with algae.


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## jake21 (Aug 11, 2019)

Hum. I wonder - they do have different pieces and types of wood. Would that explain that decay that occurs in the white tank (and why hornworth does't grow well) ? I'm not overtly concern about hornworth itself but rather the brown smudge that coats everything that is floating.


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## Broseff (Mar 14, 2021)

I'm not sure. I just know that's what worked for me. Idk what was wrong with the wood I had, but it was causing issues. Maybe there was an algae bloom? It sometimes happens with newer pieces of wood. I know some people soak wood for months before every putting it into a tank.


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## jake21 (Aug 11, 2019)

Ok thanks. These two tanks have been setup for 18 months and the wood in them have been there for at least 14 months - I mean it is possible that the wood leaches something that triggers the bad behavior but it would be a forever thing at this point.


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## pauld738 (Jan 4, 2019)

Since both your tanks use CaribSea substrates this may not be the issue but I will relate my experience just in case as I think CaribSea substrates have issues from time to time (maybe more like batch to batch).

I ran a 20 gallon with some CaribSea Eco-complete in it. I know that's different than what you have but Eco-complete is supposed to be inert and good for aquatic plants. That tank had much of the same issues you are describing. Some plants struggling to grow. Hornwort struggling, brown mushy leaves and weird algae growth in general. I noticed in this particular tank pH, well really kh, stayed high. Even though I would do water changes with pure RO water trying to get it down. Gh stayed high as well. I wonder if there are any differences in kh/Gh between your tanks? Could be a grain size, impaction thing as well? But then why does Frogbit suffer?

I switched out the Eco-complete, which did not have any sulfur smell to it. Same plants. Same wood/decor (my wood looks similar to yours?). Same light schedule, water changes, feeding, etc. Algae growth basically non existent and plants growing. Floating or otherwise.

Here's my tank before (only shot I could find, pH monitors are there showcasing how they can be off from unit to unit)










And here it is today, about 3 months after substrate change.










I hesitate to point the finger at CaribSea as my experience is in no way scientific but man do all the signs indicate it was exactly that. 

And I'll just say that I too have a piece of wood rotting in one of my tanks (10 gal pictured taken right after a trim and water change) that produces some sulfur and I'm not getting any of the issues you described. Of course my setup is drastically different than yours.

I have seen it mentioned that sulfur quickly becomes non toxic once it is introduced to oxygen so the fact that your frogbit suffers has me thinking it might be something else?










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## jake21 (Aug 11, 2019)

Only one of the two tanks has carbisea - the black one is estes stoney river. Having said that i do have a 120 that has eco-complete - that is a high-tech tank and does not have issues described with the 29 nor would i expect it to have the same issue given how coarse eco-complete is (there is actually two eco complete - red and black - i think the difference extends beyond colour but not sure. Having said that I'm not a fan of eco-complete because it is too coarse. 

I'll measure the kh/gh in the tank later and get back - that is something i should check. Good suggestion. Btw this is the 120 - a total mess but decay hasn't been an issue (it has been set up for 22 months):














pauld738 said:


> Since both your tanks use CaribSea substrates this may not be the issue but I will relate my experience just in case as I think CaribSea substrates have issues from time to time (maybe more like batch to batch).
> 
> I ran a 20 gallon with some CaribSea Eco-complete in it. I know that's different than what you have but Eco-complete is supposed to be inert and good for aquatic plants. That tank had much of the same issues you are describing. Some plants struggling to grow. Hornwort struggling, brown mushy leaves and weird algae growth in general. I noticed in this particular tank pH, well really kh, stayed high. Even though I would do water changes with pure RO water trying to get it down. Gh stayed high as well. I wonder if there are any differences in kh/Gh between your tanks? Could be a grain size, impaction thing as well? But then why does Frogbit suffer?
> 
> ...


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## pauld738 (Jan 4, 2019)

I love that overgrown jungle look! 

I think I got mixed up when looking at moonlight sand on amazon. They suggested the stoney river to go along with it and I thought they meant CaribSea. Didn't see the Estes, even though it was probably right there front and center. Of course now I'm convinced it's the CaribSea causing your issues but my perspective is rather biased, lol!

Super interested in hearing what, if any, differences in water params you might have between the 2.

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## jake21 (Aug 11, 2019)

Ok gh and kh were the same between the 2 tanks (7 gh and 3 kh) ph was .1 higher in the white tank - i used my ph pen so i don't really trust the absolute value but the relative is what we are looking at here.


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## Deanna (Feb 15, 2017)

Are the lights, light settings and photoperiods identical on both tanks?
What are the NO3 and PO4 readings for each tank?
What are you dosing and is it identical for each tank?
What is your filter setup (media) and how often is it cleaned?
How often do you vacuum detritus from the substrate surface?
Do you have good circulation and good surface rippling (for gas exchange)?

50% w/c twice a week is too much for a low-tech setup, but let's see what your answers are to the other questions before addressing this.


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## jake21 (Aug 11, 2019)

Lighting is the same.
NO3 is higher in the black tank - probably 10 vs 15 or 20 but exact measurement is difficult with api test kit.
PO4 not sure - i can measure it tomorrow
Filter is per picture HMF - they are squeezed out approx once a year - last time was about 5 months ago.
I do a water change twice a week and try to get surface muck on the substrate - since i discovered the white tank was compacting and trapping sulfur gas (about 3 weeks ago) I have started to make an effort to 'deep dive' into it to keep large pockets from escaping and allow a lot of the trapped gas to escape through the python.
Both tanks have the same circulation via the jet stream on the hmf and sponge filter in opposite corner - is it good - i don't know - i had to turn it down a bit to allow frogbit to grow in both tank - are they identical - i would guess they are close as i don't have a way to measure it exactly.



Deanna said:


> Are the lights, light settings and photoperiods identical on both tanks?
> What are the NO3 and PO4 readings for each tank?
> What are you dosing and is it identical for each tank?
> What is your filter setup (media) and how often is it cleaned?
> ...


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## pauld738 (Jan 4, 2019)

jake21 said:


> Ok gh and kh were the same between the 2 tanks (7 gh and 3 kh) ph was .1 higher in the white tank - i used my ph pen so i don't really trust the absolute value but the relative is what we are looking at here.


Well there goes that. 

Definitely intrigued on what the issue may be. I can't imagine plants issues would be due to hydrogen sulfide but we're getting out of my comfort zone on that one.

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## Deanna (Feb 15, 2017)

What are you dosing and is it identical for each tank?
Tell us more about your lights (ideally: PAR and PUR values): what type and model?
How deep is your substrate?
Let us know what your PO4 reading is when you get it.

So, you have 10ppm NO3 and you are doing 50% water changes twice a week in a low-tech tank? In two weeks you should have close to zero NO3 unless you are dosing heavily and/or your organics are out of control. Any chance that you are over-feeding or do you have that much decaying plant matter?


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## jake21 (Aug 11, 2019)

The lights are fluval 3.0 which run 8 hours a day (they start up at 8am reach full at 9am run till 4am then start down till 5am when off using the plant profile. Don't have a par meter but debating getting an apogee 510 when it goes on sale. The substrate in both tanks is around 2 1/2 inches. I does thrive-C between 4 and 5 pumps once a week and 2 pumps of iron once or twice a month. 
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My water changes in the 29 are roughly 50% but i have heavy fish loads - esp in the guppy tank.

I do not believe i am over feeding but some of the bug bites is probably getting trapped in the plants - i feed the white 29 pretty skimpy - mostly a pinch of bug bites (there are 6 sterbai and 7 kuhli as well as 6 pleco in addition to the 5 apisto) in the white tank. I feed bug bites and at night drop 1 or 2 shrimp pellets for the L333 that hides in the coconut shell.
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In the black 29 i have a lot of baby mystery snails that get up to the plants on the surface if need be - also the guppies are incredibly aggressive eaters. In the black 29 i feed flakes, bug bites for the apisto and whatever food i have that no one else wants as the guppies will eat anything they can get.
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I should have said in case it wasn't clear i do TWO 50% water changes a week - saturday and wednesday.



Deanna said:


> What are you dosing and is it identical for each tank?
> Tell us more about your lights (ideally: PAR and PUR values): what type and model?
> How deep is your substrate?
> Let us know what your PO4 reading is when you get it.
> ...


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## Deanna (Feb 15, 2017)

The Fluval 3.0 is a high intensity light, designed for a high-tech tank. It is probably the cause of much of your problems. If you over-drive the plants with light and no carbon, they will burn out, so to speak, and release organics that will help feed algae that form on the struggling/dying leaves. Combine that with what you think is a heavy bio-load, and you have a recipe for algae. Your substrate is unlikely to be H2S-ridden.

I would dim those lights by about 60-70% (if you can) if you want to hold an 8-hour photoperiod or reduce the photoperiod to 4 hours a day to see if either approach helps. I would also add Purigen to help soak-up some of the nitrogenous organics and add Excel/Enhance to your dosing regimen (helps add some carbon in low-tech setups). Dose the Thrive according to directions. Then, reduce w/c’s to once a week at 30-50%. It will take several weeks before you see any results.


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## jake21 (Aug 11, 2019)

A couple of questions - first why is it only the white tank that has issues (i want to note that these issues are not new but have been on going for over a year). Also what do you mean when you say that the substrate is unlikely to be H2S-ridden - are you saying that changes will reduce the H2S or are you saying it currently is not H2S-ridden. 
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I can of course dim the lights as they are programmable - I actually added some purgen a couple of weeks ago without seeing any benefits. Excel i will not add to this tank because of concern of impact on these fishes which are a bit more delicate. Why reduce the water changes from 2 to 1? I have fallen into this pattern because i do a 25% change on the 120 twice a week and it is little effort to pick up the 29s. 

Last but least while i have no issues dimming the fluval on the white 29 I'm not sure how you derived it is for hi-tech tanks - for a 29 the par is only around 100 at 18 inches and it is far dimmer than some of the high-end lights like the chihiros or onf flat. Conversely i could replace the fluval 3.0 on this 29 with beamwork or similar if you think that will help.
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I'm not disagreeing with your suggestions I just want to understand the logic of each items. 




Deanna said:


> The Fluval 3.0 is a high intensity light, designed for a high-tech tank. It is probably the cause of much of your problems. If you over-drive the plants with light and no carbon, they will burn out, so to speak, and release organics that will help feed algae that form on the struggling/dying leaves. Combine that with what you think is a heavy bio-load, and you have a recipe for algae. Your substrate is unlikely to be H2S-ridden.
> 
> I would dim those lights by about 60-70% (if you can) if you want to hold an 8-hour photoperiod or reduce the photoperiod to 4 hours a day to see if either approach helps. I would also add Purigen to help soak-up some of the nitrogenous organics and add Excel/Enhance to your dosing regimen (helps add some carbon in low-tech setups). Dose the Thrive according to directions. Then, reduce w/c’s to once a week at 30-50%. It will take several weeks before you see any results.


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## jake21 (Aug 11, 2019)

Ok i measured phosphate and in the black tank i had something between 0.5 and 1.0 - lets call it midway. In the white tank it was below 0.5 probably less than 0.2 - this is using the api test kit. I programed the lights to reduce the intensity by 25% - if i remember correctly the intensity of the light vs par is not linear but without a par meter i can't actually measure the par. I'm still perplex by the idea of too much light 'burning' out the plants since as i've noted i've had 0 issues in the black tank and these are well established tank so the black tank has a bit of history. In fact the only reason the black tank isn't denser is about 8ish weeks ago i had to treat the tank with furan-2 which killed off most of the non rhyzom plants and it is now picking where it left off with hornworth growing well as well as floaters (these were small bits transplanted from other tanks).


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## jake21 (Aug 11, 2019)

One more thing I wanted to add - i have a 5 gallon tank that has been set up for about 3 months that has 4 ember tetra; 7 neon tetra and some small guppies - maybe 5. It has one of those 12 inch black boxes on it (very bright) and I run the lights 6 hours a day and it has none of the issues in the above white tank - no decay - no bba - ... The frogbits in it has roots that grow to the substrate at the bottom (i once measured the roots at over 16 inches long) all crystal clear and white. It also has about 15 young mystery snails - the substrate is also moonlight but barely 2 inches - maybe 1.5 inches if i'm lucky. It has a few swords and anubia in it. The nitrate in that tank has been running below 5 - i do a water change on it barely once a month if that and the change is usually around 1 to 2 gallons - probably mostly closer to 1.


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## pauld738 (Jan 4, 2019)

I run several low tech tanks with ~ 5ppm nitrate or less. Floaters with roots as you describe. Can't complain with plant growth.

With everything you have said, I would lean very heavily in switching out the substrate. I know I fought the weird algae, browning of hornwort, etc, for awhile. Night and day difference after I switched. 

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## Deanna (Feb 15, 2017)

Dangerous substrate conditions are somewhat rare and usually confined to organinc/active substrates. Inert substrates shouldn’t have it, at least it should extremely difficult to creat, especially with your cleaning activities. Symptoms would not include decay of plants (floating plants) that are not in the substrate. Generally, symptoms such as blackened roots or decay isolated in the plants segments closest to the substrate.

Why the white tank has no issues, I can’t comment upon, but the plants may be hardier for whatever reason. Comparing the two is hard because you have different types of bioload in each, which I believe is more impactful that the difference in the substrates. BBA usually occurs where plants are struggling.

Two 50% water changes a week will constantly destabilize the tank, that’s bad for plants and may be bad for fish unless you are keeping TDS relatively stable. Two 25% are much better but, in a low-tech rank, I don’t see the need. I’d focus upon getting the plants healthy, instead of fighting algae.

Substrate-level PAR of 100 is very high. For low-tech it should be a max of about 50.

The low PO4 in the tank is probably due to w/c’s and does support the idea that organics are creating the high NO3 in relation to the heavy w/c’s. We generally like to see an NO3 : PO4 ratio of 10:1 or less.

The small tank may or may not have high PAR. It is very difficult to tell visually. The w/c is more appropriate for low-tech than 75% a week.

This is only my opinion. If you think it’s the substrate, change it out and see what happens after a month or so. It is not impossible that your substrate has gone bad, just very unlikely.


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## jake21 (Aug 11, 2019)

Ok. yesterday i went through the effort and replaced the substrate with torpedo beach. The root structure of one of the aponogeton and the dwarf lily were quite massive and i did a poor job of burying them but I'll clean it up in a few days - it was a long day with the regular water change. I waited a while because some aspect of the tank seemed to be improving and it is rather disruptive but in the end there were a few deal breakers that made me go through with the effort. The old substrate was actually quite foul and there was a substantial amount of gas trapped down there so it was probably the right thing - this will also give me a year before I move to evaluate if torpedo beach is both coarse enough to breath but fine enough for the kuhli's pleasure. 
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One thing that might have fouled the white tank is that the tank broke 4 or 5 months ago (aqueon quality sucks) and i had to quickly replaced it - this caused a lot of crap to get mixed into the substrate that might have compounded the issue. Also my other tank with the same substrate has a tone of trumpet snail which might help that tank. 
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Anyway realistically it will take at least 2 months from now for me to evaluate if this cleans up the issue:


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## Plinkploop (Jan 24, 2021)

Love your analysis of it and approach, following to see progress as I love seeing how substrates react.


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## jake21 (Aug 11, 2019)

This is my final update. Here is the current state of the tank:








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A few comments - the one leaf with bba in front is an old leaf with old bba - as far as I can tell there has been no new bba since i changed the substrate. The rock on the sponge filter is because i added a new sponge filter (the old one is being used in a pail to treat some ill fishes) and will be removed later today when the filter gets water logged. The growth has been slow but decent (you can see the state three months ago above). The lace plant is growing well. The tiny sword on the far right dropped all its leaves and is now growing new ones. The guppy grass on the right tends to collect a lot of crud. Kind of a pain since i have to hand hold it when vacuuming else it gets shreded by the python. You know how snakes are always making a mess. The pleco in this tank (there are 2 red bn - one visible and 2 L204 love zuc enough they actually come to the front and show themselves but otherwise stay hidden). Of the 7 kuhli i have in there i've only seen one the past 3 month - i'm sure all 7 are fine - it was like that before i changed the substrate. The L333 is in the coconut shell - in the evening i drop a couple of pellets outside his cave and he'll dash out grab one and take it inside. If i fail to feed him a pellet he will show himeself and wait to be fed. This tank actually has 20 fishes see how many you can find ...


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