I saw your thread flighty, im as new as you if not more so to saltwater so I dont want to tell you wrong. As of now we are shooting to order in 1-2wks...so there is still time... you can try putting a small amount of alk buffer or kalk and and watch is circulate to get an idea of where your dead areas are, but you probably already know that. Make sure you dont use much...other then that for flow, i have never got a good definition of what is needed. From the descripion of these that we are doing the buy for it looks like they really dont leave much dead stops, but are very powerful at the head. It looked like on could easily to a 75 gal. 120+ you probably should keep asking...does anyone own these? can you help us out...