Max gph for a 55?

[ReefDude]

I have a extra pump on hand and am currently converting my 55 freshwater to a marine tank. The pump is a Little Giant 4-MDQX-SC, capable of about 1500gph. I know this is too much for the tank, but I could throttle it down.... What is the max gph for a 55gal w/ 20gal sump? I will be using 1 1/4" overflow tubing, 1" feed to pump (from sump) and 3/4" return.
Thanx

[Xwild]

For starters, Welcome to TRT if I hadn't said so before.

Whereabouts in NY are you? There's quite a few NY reefers around.

I'm not sure if there is a "max". I've got a 54g that I'm hooking a 3MDQX up to. Just have to figure out how to get the overflow to handle it. (or go otb closed loop). I've been told, somewhat kiddingly, proper procedure for making sure you have enough flow.. Keep adding flow till it sloshes over the sides, then add just a touch more.

Ted

[ReefDude]

Wanted to make sure I could use that pump... no way am I getting another....
Thanx

[David Grigor]

I wouldn't push 1500gph through a single overflow hole. Regardless if it can handle it or not. You really need redundancy in case one gets clogged or partially clogged. Things happen and need to be prepared for the worst.

There are lots of philosophies on flow. I use to use a 2700gph return pump on a 190g tank going to multiple return nozzles. Plumbing more complicated lose pump output from headloss. I now prefer to handle most all the circulation in the tank and run much slower gph through the overflows/sump.

IMO: Running 1500gph going through your overflows and sump is way overkill for a 55. You don't need that much turnover going through the whole system and the more gph you push througth the sump/overflows more things can go wrong.

However 1500gph is not necessarily overkill for overall flow IN tank depending on what your going to keep.

IMO: You would be better served using the pump as a closed loop for circulation so that it is not pushing any limits on the sump/overflow and get a much smaller pump ( around 500gph ) for the return. I am never in favor of slowing down a pump just seems like a waste.

Another option would be to try and T off the output to use for a skimmer or something.

[dryheat]

Yes the post above is a great idea! I saw a 55 with that kind've setup. He set it up with a tee with and two valves so he could control how much went to the skimmer and how much to the tank. I guess in all reality you would really only need one valve for the skimmer and could just let everything else go to the tank.
- I have a question though is it better to use 3/4" or 1/2" for the run up to the top of the tank.

[ReefDude]

I'm not going to run 1500 thru the tank. I'll throttle it down... Don't have the $ for another pump right now. I have dual overflow lines if something does go wrong. I prefer 3/4" pipe unless u have a really small pump, it's less restricting.
Cheers

[ReefDude]

Actually I prolly could get a mag.... already drilled holes in the floor tho.

[David Grigor]

Originally posted by ReefDude
I have dual overflow lines if something does go wrong.

That's a pretty important piece of info that you left out of your original post when asking if it can handle the flow.......