for tom barr's EI which I use search estimative index on google, it's a method without using test kits and judging from your plants conditions you add what is needed, the pps is on the other hand is a method where everything including the substrate is inert so you have to go strictly by test kits, in my opinion, pps costs more money, good test kits, ro water and everything. PPS and EI are the exact opposite of each other, both gives good results.
Lydia, you can add plant tabs to your existing gravel, to help with plants.
John
|