Thanks Kirk and I will checkout that book soon. Currently I have a 130gal reef tank with metal halides and VHO's. I am running a Berlin XL skimmer with an iwaki 30rlt pump and a reef devil etss skimmer as well in my 80 gal sump. I have about 12 fish and 20 soft, hard, and nems. Looking to gain a lot more knowledge from this site.