The flourish dosage is also twice per week? Seachem recommended using flourish trace on the days I don't dose comprehensive. Is that necessary? If so is there a formula to calculate that dosage ?
I agree with Diana. Use trace or comprehensive but not both. Comprehensive is the micro nutrients.
Typically you dose macros (Nitrogen, phosphorus, and potassium) and micros (everything else) on alternating days i.e.
Sun 50% water change, no dosing
For future reference you may want to consider dry fertilizers. They are much cheaper.
From this package NPK + CSM+B Package - NilocG Aquatics
$14.00 you can make the following,
8 bottles FLourish Nitrogen $87.84 @ $10.98/bottle
8 bottles Flourish Potassium $87.84 @ $10.98/bottle
78 bottles Flourish Phosphorus $768.30 @ 9.85/bottle
9 Bottles of FLourish Comprehensive $98.82 @ 10.98/bottle
$14 versus $1042.80...Your choice
Flourish Nitrogen 500ml KNO3 54.14 grams (approximately 10 1/2 teaspoon)
Flourish Phosphorus 500ml KH2PO4 2.88 grams (approximaetley 1/2 teaspoon)
Flourish Potassium 500ml K2SO4 53.65 grams (approximately 8 1/2 teaspoons)
Flourish Comprehensive 500ml Plantex 24.5 grams (approximatley 5 3/4 teaspoons)
Edit: I forgot to mention my previous post where I said the potassium doses were correct was wrong. The percentage in Flourish potassium is listed as K2O not potassium. To convert K2O to potassium multiply by 0.8301, Conversion factors