Adding Marine pure block to frag system

[FishOfHex]

I dont have a ton of room for live rock in the 40 gallon frag system so i decided to add an 8x8x4 marine pure block.. That should be plenty of surface area

 

[ThePriceSeliger]

I almost think they are too effective. I had two 8x8x1 sheets in my sump, and with moderate skimming I was never able to elevate any nutrients. Removed one and moved the other to a very slow flow area of my sump, I've been able to see some po4 now.