So long story short, I've been dealing with BBA/GBA for quite a while and can't seem to figure out how to stop it.
Before I get too far into it, yes I have CO2 running (it's DIY so there is a slight variation in daily CO2 levels, but the drop checker is always close to lime green), and have about a 1 ph drop when the CO2 is running.
I recently moved about a month ago and was hoping a newish setup would change things for me, but that unfortunately hasn't been the case. I've been fighting BBA/GBA for what seems like months to no avail. About a month before the move, I swapped out 50% of my substrate, changing from Eco-Complete to Tropica. A week before the move, I started cycling a bucket of ADA Amazonia (couldn't find anymore Tropica) and then replaced the other 50% during the move. During the move I also replaced probably 50% of the unhealthy plants, and kept a number of the plants that were less affected by the BBA. A month into this new setup, and BBA is starting to take over again...
20G long w/ Kessil a160 6" above the water @65% power 6 hours a day. No direct sunlight.
pH - 7.5 w/o CO2, 6.6 w/CO2
Ammonia - 0
Nitrite - 0
Nitrate - 30
kH/gH - 4/7
Dose Thrive+ 1 pump every day (suggested is 2 pumps 3x a week for 20 gals)
50% Water Change 1x week with tap water treated with prime.
Plants: Rotala Rotundifolia, Ludwigia Arcuata, Cypt Wenditii Red & Green, Narrow Leaf Java Fern, Anubias Nana Petite, Buce (green wavy, and ghost), micro sword.
Prior to the move I had tried pretty much everything with regards to fighting the algae with no avail including reducing lighting intensity/length/distance from surface. Current situation is that the microsword is failing to carpet as it's just getting covered in BBA and BBA is starting to cover all the Anubias/Buce. The Rotala seems to be doing slightly better as there isn't much Algae on there, but the Ludwigia is still having issues.
I've been completely stumped up to this point, until I came across a thread the other day about stocking. Right now I've got 9 neon tetras, 7 coryadoras, 1 otocinclus (used to have more...), 3 amano shrimp, and 2 nerite snails. Is this too much for a 20g? I've got a Cascade 700 Canister filter running max flow(265 gph)
Even with this filtration, is it possible that I am overstocked and that is what is causing my constant battle with BBA/GBA? If not, does anyone else have any suggestions?
Here was the tank day 1 after the move, stems have grown in a bit but other than that it looks pretty much the same just with more algae....