Moisture / PH Content / Light Meter Soil Plant 3 in 1

you doing hydro just figuring cause you said flood tank?

cause thats for soil.

if your doing soil id just get a reg PH tester 8 bucks on ebay

Or you can get a PH tester at Home Depot for like 3-4 dollars. PH your water, then give your plants a dose of water. Collect the run off and you got your soils PH. Has always worked for me.