Bacteria keeps dying. Help/Advice

Background info I cycled the empty 23 gallon tank for a month before seeing Nitrates and added fish gradually. 10 Cherry shrimp, 13 neone tetras, one Beta and two Sword tails. I feed the fish twice a day. AMOSIJOY 172GPH Canister Filter, with a floss pad, carbon sponge, ceramic filter rings, and Bio balls.

My problem is that my bacteria seems to die every 2 weeks or so. I see my Nitrates fall to zero, then the ammonia starts to go up slowly. I was told that maybe my filter is doing too good of a job and starving the bacteria. Is that possible? I keep having to add bacteria to the tank and I am wondering if I should just add more fish to creat more waist. I think the ammonia spike caused the beta to get a touch of fin rot, I am currently treating him for it and he is doing well. Adding the Nitrate/Nitrite readings for this tank (left) and a shrimp tank (right)

TLDR: Bacteria dies off (I think it's being starved), should I add more bio load or change the filter to something else. Also, is there something that may be killing the bacteria?

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u/falcon_311 8h ago

Excessive filtration isn't a thing, bacteria dont crash because fish don't produce enough waste as they populate to the availability. Its a normal ebb and flow of nitrifying bacteria populations. This only leaves you with something it sounds like you are already suspecting. You are doing something that is killing the bacteria and you just don't know it. It could be using an aerosol in the room for cleaning, putting your hands in with antibacterial soaps still on, etc. You just have to find what it is.

What is the water change schedule like? Is it a new problem or has it happened since the begining?

Also 0 nitrates is not a bad thing at all. It only means the plants uptaking the nitrogen faster than it's being replaced. This stuff is not food for bacteria anyway, it's the ammonia and nitrites that are. After that, the nitrates become useless for the bacteria as it is far too oxidized and is of value only to vegetation.

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u/Arcangel100 8h ago

I top off the tank daily and water change about 10% every week. The canister filter gets cleaned every three weeks or when I notice shrimp have disappeared (they like to jump in from the skimmer but they are always unharmed). Hmm maybe I am killing the bacteria somehow. I try to not rinse off the ceramic or bio balls. I just set them aside while I wipe the canister and change the floss pad. The only reason I am asking is because my Betta got a touch of fin rot and I correlated it to a spike in ammonia of .20ish.

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u/falcon_311 8h ago

Ro top off or with treated tap?

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u/Arcangel100 7h ago edited 7h ago

Yup, I use Top Fin water conditioner for every water change.

Edit: it's tap treated water in NY city.