How to higher the nitrate?
I have my 20L tank with CO2 about 3 bps, Lights about 7 hours per day, Dossing Excel 5ml daily, Flourish 2 ml every pairs other day, 1ml Seachem Iron every other day as well, Seachem Potassium 1 ml each 3 days, Wate change 1 per week 50%. Substrate Fluval Stratum.
PH 6.8 before CO2
PH 6.4 after CO2 by the end of the day
What i am doing wrong? How can i raise the Nitrate numbers to archive 25-30ppm ??