turnover rate

I have a COR20 on my 100 gallon DT, 34 gallon sump (it's trigger sapphire 34). Whenever I do any sort of dosing, I generally just say 100 gallons. I've been having a problem with high nutrients. For example, my phosphates yesterday were 0.34ppb (Hanna ULR). I run GFO mixed with Carbon in a...

New tank, 75g + 25g water in sump, just completed cycling with only 2 clowns currently in tank. The tank came with 2 Koralia Evolution 1150 powerheads. I purchased a Varios6 return pump... have it set on level 2 right now. The Varios6 has approx 1000gph at 5ft head pressure...I figure on the...