Ok, part of my attack on the BBA in my tank is to stop doing monthly water changes (30%) and instead just operate on a "top up" basis. To do that, I probably need to drop my dosing level. At present I'm doing 20ml for 190l every week of all-in-one ferts (James' recipe #3). Given that the dose is pretty high for a low tech tank, I have used the water changes to keep the TDS at something vaguely sensible (usually around 500/600). What's the best way to go about reducing my fert load? In my mind there is probably an amount that's just pure excess across the board, but I bet some aspects of the fert are utilised by the plants since they've been available? If so, I'm guessing I'd have to very gradually reduce my fert dosing so that the plants have time to adapt? Any pointers welcomed! Cheers.