Mag 12 plumbing help

[ultramafic]

I've finally purchased a new return pump, my old one burned out and i've been using a little baby catalina pump to limp by in the meantime. I'm running a 225 mixed reef with a 40 breeder as my sump, and i'm about to install a Mag Drive 12 as my return pump, with a T off to feed my carbon reactor. My question is this:

The outlet for the pump is 3/4 fitting, but the paperwork says for maximum flow to use 1.5 inch piping. So my plan is start with the 3/4, and i'm going to T off the feed for my carbon immediatly (with a gate valve to adjust the flow) and then use a coupler to go from 3/4 to 1 1/2 for the rest of the run to the top of the tank, and then have a manifold at the top of the tank that splits the return into 4 different 1 inch piping returns.

Is this necessary? Will i be getting more flow with the bigger piping or should i stick with the 3/4 the whole way? also will splitting my returns up using multiple 1 inch piping be restrictive as well? I'm not afraid to run back to the hardware store so if anybody has experience with this please feel free to tell me dump all my plumbing and use a garden hose. mucho aloha!

p.s. i've been scouring the internet for the answer and i've read answers from both camps. "3/4 the whole way, changing the piping will reduce the pressure!" "bigger piping better flow!"

 

[kgross]

Yes you will get more flow from the larger pipe. Go to the bigger pipe quickly. Get a 3/4 FPT to 1.5 inch slip bushing and go up to 1.5 inch at the pump, then do your T's and valves to get the max flow.

Now is it necessary, no, only if you want to get max flow from the pump. If you keep with 3/4 inch piping guessing 4 feet of vertical height you will get a max of 790 gph, with 1.5 inch pipe your over 1010 So do you want the extra 200 gph out of the pump?

 

[ultramafic]

okiedokie. My hardware store doesn't have a 3/4 Fpt to 1 1/2 or anything to T off of a 1 1/2 unless i step down 1.5 to 1.25 to 1 to .75, so i'll have to go hunting tomorrow for some goods. I bought the bigger pump so that i could use it at its full capacity, so bigger piping it is! my return pump now is pushing maybe 300 gph so my skimmer and sump have been on vacation for the past 3 months, can't wait to get a little flow through my fuge and utilize the flow from the returns.

Question is it absolutly necessary to go directly to the bigger piping or can i T off for the reactor straight from the pump and then step to bigger piping? I guess thats the lazy in me, maximum flow means bigger piping all the way.

 

[kgross]

Is it absolutly necessary to go directly? No, as I said if you want max flow you want to move up in size, any 3/4 inch piping will restrict the flow over the 1.5 inch piping. How much flow difference will it make I have no idea to be honest.