Wow, thanks thats alot of help. Actually my reef tank is 90, my refuguim is about 45, the tank for the octopus is about 35, and i want to get anouther 20-30 hooked up. I was estimating actual amount of water not including live rock. the tank for the octo is a 35 gallon (i think) hexigonal tank and does not have too much floor space because it is kinda tall. i already have a skimmer but i dont know what it is rated because it was given to me with the reef tank i have.