I am new to hydroponics and aquaponics. I've supervised drilling of six water wells and designed/ built various water storage and delivery systems in the 60psi/ 60gpm range. I have also built fountains of many kinds. The koi ponds I have built used about 2 yards of 3/4" crushed gravel as a biofilter, as well as a sand filter. The gravel is removed, washed, and replaced annually at considerable effort.(which I am no longer involved with!) I am very interested in the incorporation of…