I been in the hobby for about 2 years now. And have started last year to do planted. My tank is heavily planted right now w/ regular gravel. I have been dosing .5ml or 1/8 tsp of KH2PO4, K2SO4 & KNO3 every MWF; 1/8 tsp CSM+B every TThS. 50% water change every Sunday. I have the lights on for about 8 Hours. My PH is 6.2 to 6.3 w/ the CO2 on. My question is am I dosing enough ferts? My plants are growing but most of the Amazon & Nana keeps getting "black spots" on the leaves. I tried rubbing them off but to no avail. One more thing I just purchased the PMDD Pre Mix from Greg & was wondering how to dose w/ this since the Micro & Macro are already mixed? Thanks.