Co2 Won't Drop?

onlyplants

New Member
Jan 6, 2020
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Prague, CZ
Can anyone help me troubleshoot my grow out tank for some buce and anubias?

It's about a year and a half now, and from the last 6 months, plant mass has started to decline. No matter what test or ph pen i try, I can't get more than half a point of ph drop (resting is 6.5, it sometimes goes to 6.0 after the co2 shuts off but never lower). The outlet of the filter is totally cloudy from microbubbles, I've checked for leaks, and everything seems okay. the first 3 months were hugely successful with almost every plant flowering, but eventually I started getting unmanageable algae, so I stopped dosing and now that the algae is gone, but plants aren't impressed. I'm up for going back to EI, investing in better lights, or whatever - but I will need to fix this co2 issue first. To me this seems like a very basic issue but somehow I just can't get past it.

Some info about the tank:
40g, inline diffuser @ about 10bps. Oase biomaster 600
30W of some rip off LED. I tried as hard as I can to get the manufacturer or light specs, with no result. They only advertise "2862 lm".
6 hours of light, 7 hours of co2. co2 goes on 2 hours prior to lights, and shuts off an hour before the lights go off.
3 big pieces (forearm sized) of unknown wood. It's very soft, and i can easily scratch dents in it with my fingernail, bought from LFS. It's kind of making a mess and algae is growing more on this than anywhere else.
3 fist sized pieces of granite holding the wood in place
2-3 cups of aquasoil in the back for crypts, with a very light layer of pool filter sand covering the bottom of the tank.
happy colony (maybe 30-60) RCS, 1 betta.
Tank has about 20-30% plant mass. Java fern, crypts, moss, anubias and buce.
I do about 10 big sprays of h2o2 after every water change, weekly.

My original assumption when algae started picking up, is that my dosing wasn't right. So i measured it all up, checked it twice, and then bought a cheap dosing pump where i dosed macros once a week and micros daily, as per some advice I read here, along with a co2 reactor. Algae returned, just as it did in the past. The only thing that's left is that this is the result of inadequate co2. But no matter how much i increase it, i can't get that drop. Any advice to help me move forward, at all? I'm tempted to reset, but this is a problem that should be easy to fix and I don't want to miss out on a good learning opportunity. Why am i struggling? How can I make this thrive?

Thanks.

edit:
I totally forgot about a post I made about this tank a year ago. Since then, it's been mostly fert free. Though there has been some growth since, the same issue persists.
https://barrreport.com/threads/tank-cloudy-with-co2-but-getting-bba.16998/#post-159693
 
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CRS Fan

Junior Poster
Feb 15, 2010
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Vancouver
I would suggest cleaning/replacing the diffuser and see if that helps. I used to soak my Up Aqua diffusers in bleach and then dechlorinate it using Prime. The Qanvee ones you can replace the actual diffusers. It might just be a porosity issue. I hope that helps.

Best regards,

Stuart


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onlyplants

New Member
Jan 6, 2020
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Prague, CZ
Hey, thanks for the response!
i first had the standard ceramic diffuser, then because I couldn't get the ph to drop, I got the new up aqua inline diffuser. When I made that thread above, someone suggested to get a reactor, so i did, and got the same issue, but with much more added noise, so i put the inline one back on. None of them would drop the ph a full point. After posting this message, out of frustration, i totally reset. I took everything out, substrate included, scrubbed the wood with a wire brush and got rid of all the decaying matter. h2o2 dipped the plants, cutting off anything not 100%. Today a new day, i tested several times, and actually got one of the best ph drops. I checked it before the lights went on and it was 6.6, then 4 hours later (i checked it every hour or so), it was 5.9. Shouldn't this ph drop only take an hour or two tops? why does it take so long and how is it that some people are using 3bps and I'm using closer to 20? There has to be something i'm missing?

Anyways, since it doesn't hurt, the diffuser is soaking in 30% bleach. I'll let it sit for 30 mins, give it a proper rinse, hit it with some safe then stick it back in and will report back tomorrow.
 

onlyplants

New Member
Jan 6, 2020
21
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Prague, CZ
So far co2 has been on for 2 hours. here's some details. I tested everything twice with a ph pen, tds

Resting ph 6.5
working ph (2 hours after co2 goes on) 6.2. 2 hours after that, so 4 hours of co2 being on, it's at 5.9, where it's stable.
Kh about 3.5. indicator was "slight" yellow at 3 drops, dark yellow at 4.
tds 234

co2 is rushing out like exhaust from a car and the whole tank is full of microbubbles. Mind the dirty glass.
131972227_417875329566539_8041564116411017135_n.jpg
 
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onlyplants

New Member
Jan 6, 2020
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Prague, CZ
with the above being said, a calculator suggests that I have around 70ppm of co2, which should be quite huge. If that's the truth, (and it seems like it is) then why is are anubias and buce melting? The betta seems fine, not hanging out at the top too much (unless he's begging) but the shrimp population, after the reset is definitely going to take a hit.
Is it safe to rule out that co2 is sufficient? Can I even turn co2 down a bit so i can make my tank last another month or so, and resume EI?

I still don't understand why the pH won't drop, but does that matter at this point?
That brings yet another question, if the tank has 6.5 ph overnight, the "resting" co2 concentration should be around 30ppm. How can that be? Could my ph meter be off? as an experiment i put my ph meter in an old thing of distilled water and it came out at 7.4. I'm not sure if ph increases over time. This ph meter is only a year old. I've used it about 20 times and haven't configured it since the original out of the box solution.

I'm sorry that this seems like a conversation to myself but there's so many oddities here and i can't find anyone asking these questions, and thus no answers :(
 
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onlyplants

New Member
Jan 6, 2020
21
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Prague, CZ
Any help here? I'm at a loss. I don't trust these co2 charts and everyone swears by the ph drop but I can't get it.
Should I gut the tank, fill it with bare bottom tap water and see if i can get a point ph drop then?
 

Richard Jones

New Member
Oct 26, 2020
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Austin,TX
I don't understand why you are so worried about a pH drop when your pH levels judging by the CO2 charts looks good. I'm honestly a noob to planted tanks, so part of why I ask is to learn of there is anything I'm misunderstanding.

It seems to me that your "resting" CO2 is already near 30ppm, so overnight you aren't gassing off enough CO2 to get back to atmospheric equalibrium. Perhaps adding an airstream overnight would increase your pH by the morning?

It also sounds to my nooby self that the CO2 isn't your issue, so it is either light or nutrients. Or maybe even that your water is too acidic for those plants.

I hope it's doing better already since it's been a couple of months.
-Rich

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onlyplants

New Member
Jan 6, 2020
21
1
3
39
Prague, CZ
For anyone wondering, I tried several things
Switching from EI to APT complete (dennis wong). Gave it 3 weeks
increasing co2 until the single fish was gasping, then turning it down just a touch. . Just couldn't see through the tank with all the microbubbles.
Daily water changes

nothing helped. There was no leaks in the system, ph still wouldn't drop more than half a point.
I did a full reset on the tank with only water. 2 hours of co2 dropped the ph 1 full point. Filled the tank back up with Platinum soil (something like ADA without ammonia) and the few granite stones, all is well. Getting the ph drop, plants seem to be coming back. Lost about half of them but it shouldn't be long until they recover. Thanks for all the feedback everyone!
 
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