Re-noobie needs plumbing/return pump guidance

[milkit]

I sold off all my tanks and such about 2 yrs ago.. I just bought a new tank and I am starting over. I have never had a true drilled tank and I have some questions.

My tank is a 115g, 48"w, 30"d, 18.5" tall. It has a single overflow box in back corner. Inside the overflow are two drilled holes. It appears they are 1.75" and 1.5" in size. Looking at bulkhead dimenions that gives me one 1" pvc and one 3/4" PVC.

My question, should I use the larger for the overflow, and smaller for the return? What GPH pump should I shoot for that can be handled by those sizes? How should I plumb the actual overflow spout?

[bnumair]

the bulkhead sizes sounds more reasonable 1" drain and 3/4" return.
1" drain can only handle 960gph. so naturally u want a return pump just a hair above that

[milkit]

the bulkhead sizes sounds more reasonable 1" drain and 3/4" return.
1" drain can only handle 960gph. so naturally u want a return pump just a hair above that

thanks, any recommendations? I've been looking at the Bulk Reef Supply since they have their 10x points..

http://www.bulkreefsupply.com/iwaki-wmd-40rlxt-american-motor-1200-gph.html perhaps?

or

http://www.bulkreefsupply.com/pan-world-100px-x.html

or maybe a mag12?

[bnumair]

i have no experience with any of those pumps as i only use reeflo pumps. but u need to make sure what ever pump u go with that its flow is about 1100gph after head loss.
a 1200gph pump may only be 700-800gph after 4-5 feet of head loss.

[bnumair]

i couldnt find head loss rates on the 2 links but mag drive 12 is 1120gph at 5ft and 950 at 6ft.

[milkit]

i couldnt find head loss rates on the 2 links but mag drive 12 is 1120gph at 5ft and 950 at 6ft.

ya I had a dart on my old tank but I think it's a bit overkill for this :)

I think I am going to go with a mag 12... I will only have about 4.5' or so of head

[sleepydoc]

Acutually you want your return pump flow to be below the capacity of your overflow drain. If your overflow can carry 750 gph max and you get 750 gph from your return pump, you're asking for a flood as soon as anything starts limiting flow in your overflow drain. Also, if you're running a single drain, it should not be a full siphon and the capacity will be significantly less.

Bear in mind that you will have head loss from pipes and gravity for your return pump, so a pump rated at 1000 gph won't necessarily give you that. Consider putting a Tee and/or a valve on your return line - you can use that to throttle back your pump or feed carbon/GFO reactors, etc.

I would read about the Herbie/Bean Animal overflows and consider doing one of those.