i have found a guy that will sell me his 120RR for $300 tank and stand. :bounce::bowdown::claphands currently i have a 75 with about 70 lbs of sand and 4" deep sand bed. i have a wet/dry that has about 20gals. now i don't have the room to have both up and running at the same time. here is my plan: get one more bag of sand and mix it in with the sand i have already. put everything in the new tank. add rock (cure it in some buckets with some of the old water when i do a water change) the extra water will come from the fresh salt water that mix every week and i will just add it in. use some of the sand in the tank now to make the DSP for the refugium. have a closed loop with 2 1" outlets at the top going to two mag 7 what will be alternate and then have 3 3/4" inlets. i welcome ALL ideas and suggestions on how you think this will work

In order to keep your velocity you need your pump outlet total nozzle area to equal your pump outlet size area. You can increase your flow by increasing your pump outlet pipe size and the total nozzle exit area, but you will have very little velocity (force). Area is pi x (Diameter/4)^2, pi = 3.14 example: 1/2" diameter = 0.20 sq inches, 3/4" = 0.44 sq inches, 1" = 0.79 sq inches, Therefore four 1/2" pipes is equivalent to one 1" pipe. Another way of looking at it is velocity = (0.4085 x GPM)/ Diameter^2 Example: 600 GPH pump = 10 GPM pump velocity (1" pipe) = (0.4085 x 10)/ 1^2 = 4.085 ft/sec, and the velocity (1/2" pipe) = (0.4085 x 10)/ (1/2)^2 = 16.34 ft/sec. Therefore the smaller the pipe the higher the velocity, and with 4 small pipes you will have one fourth the flow from each pipe and v=(0.4085 x 2.5)/ (1/2)^2 = 4.085 ft/sec. wa la one fourth the velocity as if you ran it through one small pipe. All this means is if you want the same velocity coming out of multiple heads as what is moving through a 1" pipe you would need to use four 1/2" pipes. Three 3/4" pipes would only provide a velocity of 2.42 ft/sec with a flow of 3.333 GPM from each pipe. Of course I could be as entirely confused by what you are trying to explain as most people probably will be confused by what I am trying to explain.

fatman - believe it or not i understand everything you said (math degrees :bounce i will make my adjustments for what you are saying. reeffreak - whats wrong with the reverse Y

Reef is saying to use a Y fitting and not a T fitting to split the water draining into the sump. The Y will have less water turbulance than a T will. Thus allowing more flow with less noise. Brian

Sagent3000, I like math except diff eq. It is important for research. I am glad I am not a researcher. There is enough math in engineering to keep me happy.