Need help growing plants

[srobin20]

Hi, I wanted to say thank you for the advice in advance. My issue is I am unable to grow Rotala Indica and my Anubius are leaves are dying off slowly.

Environment:
90 gallon tank (Running for about 4 months)
1 Fluval plant Led 48 inch ( On 8 hours a day)
Water Temperature 84 degrees

No3 Nitrate - 0ppm
No2 Nitrite - 0ppm
Ph - 8 to 8.2( I think it is closer to 8.2)
Ammonia - 0ppm
Po4 Phospahte - 0ppm (might be 0.25ppm)

Test Strip:
Gh: 0
KH: 240ppm

KH and GH Tubes:
107.4 ppm

Dosing: Flourish twice a week and Excel twice a week (no co2)

Pictures: https://drive.google.com/folderview?...G8&usp=sharing

[pcsb23]

Not used or had any experience with the fluval light fixture.

Rotala needs a reasonable amount of light, if the led fixture is a good one, then it should be adequate, depending on tank depth (guessing around 24"). Photoperiod is a good starting point. Surprised at the annubia dropping leaves, but it does indicate a nutrient deficiency - normally annubias are pretty bullet proof.

Plants require light and nutrients like any other living organism. You are starving them. They need macro and micro nutrients. Of the macro nutrients by far the most important is carbon, but without the others that alone will be useless. You need to dose something that contains NPK, i.e. Nitrogen (N), Phosphour (P) and Potassium (K). In large tanks it is usually cheaper to use dry powder ferts. Typically these powdered ferts or nutrients are KNO3 (potassium nitrate) and K2PO4 (potassium phosphate). It seems from your numbers that you have no GH (seems very curious but ...) so you will need to add magnesium too (technically this is a micro fert but it is sort of a crossover ...), and this is usually added in the form of MgSO4 (magnesium sulphate or Epsom salts).

Plants also need micro nutrients (iron, boron etc ...) and as you are already using flourish that should cover it, albeit expensively imo! I use a dry powder mix.

The limiting factor is likely to be carbon, using excel can work out expensive but it does work, you may need to increase the dose to match the lighting.

Do a search for EI dosing (estimative index).