Hi Guys, Ever since changing my substrate to Ada Amazonia at the start of September this year i have been battling with Diatoms, so i thought i'd ask for your opinions as it's becoming too much now. My poor pogostemon helfri is covered in it at the end of each week, and the substrate amongst it. Cleaning it is a pain as the plants aren't the easiest to clean - it's a fully planted tank. My tank stats are: 76L Lighting:3x 24w T5 12 hrs a day. Substrate: Ada Amazonia Filter: Tetratec EX700, 2 foams removed, purigen added 600l/h powerhead for extra movement Dosing EI. NPK and Trace 3x a week on alternate days. 34.4g kno3 in 500ml, 15ml 9.6g po4 in 500ml, 20ml 6g trace in 500ml, 10ml PO4 was meant to be dosed at 15ml each time, but i started getting green spot algae. That went, but it's come back again even with 20ml 3x a week. CO2 is pressurised, running around 2-3 bps (too fast to be counting!!). Diffused through a rinox 1000 into the filter inlet. So far i've tried: Minimising the light - it used to be 4x 24w, using a siesta. The 3x 24W i've taken off a 52l tank which had no problems with algae with the same light period. Add the powerhead to increase the flow. Upped the CO2, although more just seems to build up in the filter. I've never fully understood this Gh/Kh thing, but the water in this area is very hard. For the first few months i did small water changes every other day. I dont have time to be doing this now, although i recently started to try adding ammonia remover incase it's due to this. Increased the 50% water changes to 75% each week. Does anyone have anything else i could try?