25ppm NO3 isn't bad. Root tabs release varying quantities of nutrients in an uncontrolled way and are not necessary. Can we get some more info in order to help you better? Please supply as much of the following as possible:
- Light (make & model): ideally, PAR and PUR reading at the substrate and photoperiod?
- CO2 setup (if any) and, if you inject CO2, what is the CO2 ppm level and how is it measured?
- Current NO3, PO4, GH, KH, pH and TDS readings?
- What you are dosing (product and quantity) and how often?
- Substrate type and how long has it been in place?
- What is your filter setup?
- Cleaning regimen (filter and water change frequency and amount)?
- Circulation: surface rippling and are all plants gently moving from top to bottom?
- What is your water source and do you use a water softener?
Please look up each of your plants to determine what, if any, special needs they may have. With this, you can see better if you are meeting the needs of the plant.