algae
I don't use CO2, I fert. with Flourish supplemental complete 1-2 x's/wk. I have 28 Watts of light, 2 T5 6700K 14 watt bulbs (25g tank), Ecocomplete substrate and water test are in the range you mentioned. I run the lights for 1.5 hrs in AM, wanna see in tank and check things out b4...