Hi, its a lighting/co2 issue IMO. Little point spot dosing, the affected leaves are damaged beyond repair.
Id be looking carefully at your co2 level and circulation. Id say its notable that the tank is 6 months planted but growth of quite a few plants looks weak. If all was on point id have expected it to be looking rampant (unless you are doing a lot of trimming).
K
I trim quite a bit, to get a more compact growth, but it should have grown more than it has.
Have been playing around with the circulation, just pointing the out flows at different angles. I'm going to do a feed in a minute which will help me see what's happening.
I'm thinking of swapping the inflow and out flow either side. As the plants aren't as high on the right.
I feel like my next moves are critical to the success of this tank.
Thanks K!