I am currently pouring 1tsp kno3 and 1/4tsp k2po4 daily into my 40 breeder to keep blue green algae at bay.
This tank has been running for 10 years, 8 of which it was neglected. It got ei level ferts, and the water was changed very rarely, the filter even less.
There was tons of bba, and the tank had a grungy look. Easy plants were happy, and the fish lived well beyond their natural life spans. The tank was lit by 2x55w cfl with AH supply reflectors, for any old geezers who know what I mean
When the cfl fixture bit the dust, I had to decide to get new lights or get rid of the tank.
I decided I could get new lights if I actually kept up with the maintenance.
For a few months now I have been cleaning it vigorously. I cleaned out the filter, did a heavy vacuuming of the 10 year old aquasoil and have been doing weekly algae removals.
Since then, I have had to dump in fertilizer to keep the blue green algae and melting leaves at bay.
40 breeder, 2x t5ho with garbage reflectors, filstar xp3, small circulation pump (new), inline co2 diffuser at 4bps