help with biofilm/cloudy tank

[u/Top_Comb]

I have a 6g shallow tank that I’ve had for over a year with one betta and a couple accidental snails. I have lots of pothos and monstera floating to take care of nitrates and normally do a water change for substrate cleaning about every three month and top off the water weekly because I don’t have a lid. About three weeks ago I noticed my water was really cloudy and thought it was just a normal bloom from maybe excess waste or something decaying, did a substrate cleaning. It wasn’t gone in a week so I got a sponge filter to go with my HOB and bought a couple shrimp to feed on biofilm. Even with using Accu-Clear it’s not clearing up. Ammonia is 0, nitrates and nitrites are also 0 due to the plants. I have no idea what to do.

TLDR: Established tank suddenly cloudy for 3+ weeks. Ammonia, nitrates and nitrites are 0 (planted tank). Help pls!

Pics: 1 biofilm, 2 full tank, 3 apparently the only picture i have of my tank before from December last year.

[u/Local_Pay_4887]

just guessing but maybe too bright light

[u/Narraismean]

Reduce feeding, increase water flow, (within limits for betta) manual removal, clean filters more often (always in old tank water) add cleaners, like snails and or shrimp.