I think it all depends on how many fish your planning to have. Remember that fish produce the most waste. If your going to max out the allowable fish that your tank will hold, I would get the skimmer and add more LR(if possible) If your going to go half way(fish wise) just get more LR and no skimmer. Either way, your going to have play it by hear anyways and test your parameters. Also, becareful of the bio-wheels, there known to be NO3 factories. I hope this has helped, Luna. _________ 9YR OLD 90G 30G w/d Mag18 150G skimmer 692w MH,yel&kole tang,foxface,midas&convict blenny,B&G chromies,Blk/yel fin chromie blackcap,nemo,neon goby,6line; Blastomussa Merleti,Acan ,BUBBLE,Torch,LTA, Goniopora(2), Acropora(2),Brain, Moon, assort zoas, yel& G star polyps, R&G open brain, P&B ricordia, montiporas, cup&candy corals, enias,B/G mush,flower ane(2), cherry red mussa, dusters,cleaning crew  |