Need help with overflow vs. pump

[ReefRex]

Hello All,
O.K. So I have decided to go with the 120 gallon tank for my upcoming “super reef”. But now I have some questions about filtration/water flow. I plan to use a rubber made sump/refuge below the main tank. So my first idea was to get two large pumps (600gph-1200gph), one pulling water to the sump and one pushing water back. But I’m now doubting how it would work, since the one pushing the water back needs to fight gravity and hens making a possibility for the one pulling water to pull too fast and make a flood, as well as the cost of two pumps. So maybe I should use an overflow, problem is that I have never used one and have no idea on how to set one up or how to use and what works with what. I have found an overflow that looks good.
http://cgi.ebay.com/New-2006-Model-Over ... dZViewItem
Is it any good? It is rated for 600gph and has a 1 inch bulkhead, so what pump and size/model would work well this? I know I would need more flow in the main and it will be coming from a bigger pump with an OM Squirt. Any ideas and advice would be greatly appreciated. And sorry once again for the LONG post. :?

 

[FragMaster]

Well in order to give you a best guess emstimate we need to know how many verticle feet of pipe your running, how many feet of horizontal pipe, and how many 90 and 45 degree angles as well as pipe diameter.
Is it going through a spray bar? Are your returns going to be split ?
Running it through a SCWD?
All of the above must be taken in to account before hand.
90 deg angle, 45 degree angles and splitting your return as well as using a spray bar all deplete head height and over all flow.

 

[ReefRex]

Well, I will not be using any 90s or 45s, it will be all soft lines going up and down, to help with flow. As for the height, it is about 4 feet top to bottom and vise versa. The return will finish with a single, very free flowing spray bar at the top of the tank. As for the diameter, I am not sure, what should I use with the type of overflow. Like I said I have no idea when it come to overflows. And no SQWD will be used, I said, “I know I would need more flow in the main tank and it will be coming from a bigger pump with an OM Squirt.” This will work in a closed-loop system. Thanks for the help.

 

[Mihai]

ReefMax,

since you're in the planning stage save yourself the trouble and go with a "reef ready" tank, i.e., one that is drilled at the bottom. You'll use only one pump to pull the water from the sump to the top tank that will overflow in the sump.

The idea with two pumps will never work - there is no way to match their flows. If you want to do things right, I strongly suggest you postpone buying anything for about 2-3 months. In the mean time read a few good books on the subject. Say, Fenner's "Conscientious Marine Aquarist"... Or Tullok (or Tullock?)'s natural aquarium book.

The more you rush the more you'll regret later.
M.

 

[Len]

Yep, if you haven't got the tank yet, I completely agree with Mihai: get a reef ready and safe yourself the headaches In-tank overflow boxes have many advantages, some of which include no chance of flooding from broken siphon and simple use (it's basic gravity at work).

The two pump idea is impractical at best and impossible to adjust properly. A reef ready aquarium plus one (or two) return pumps will make your life very easy.

If you already bought the tank without an overflow box, then you will have to go with one of the hang-on types you found. We can discuss this further if this is the case, but hopefully you're still in the planning stages.

 

[ReefRex]

Hello,
Thanks for the idea, I will have to look into a reef-ready tank. With the pump idea, the thought you had was what I was thinking and was like, “that wouldn’t work right”. Just to clarify some thing, this is not my first tank, I have done FW for over 12 years and have had my current 55 gallon reef for 5 years. I just have never used an overflow setup and like I said, I have no idea about them. I guess what I am looking for is if there is any kind of special formula to find what pump to use with what overflow. Or is there a pump that some one can recommend for the above overflow. Or some thing to read on how overflows work or info on them. Thanks again.

 

[ReefRex]

Man, I type slow. :lol: No, I have not bought the tank yet and yes I understand the use of gravity in an overflow system. But like I said, I'm not sure of the other "things" about them. How hard would it be to drill the tank, or is it just easier to get one with it already? Thanks.

 

[Len]

Basically, you just need an overflow that can handle the flow of your return pump. So if the overflow is rated for 600gph, you need a return pump with less then 600gph at the output (you need to estimate head pressure loss from bends and height). Good thing is you can always throttle back the flow of a return pump with a ball or gate valve, so it's not really super critical.

Most reef-ready tanks are drilled for 1" I.D. bulkheads. These generally allow about 800gph of flow, so get a pump in that neighborhood. As an example, on my previous 120 with a 1" single bulkhead overflow, an Iwaki 40RLXT is about the most flow it would handle.

So the idea is simple: get a tank with a built-in "reef ready" overflow. Water will overflow into the reef-ready box and flow down to the sump via the hole you have drilled in the overflow box. The water is then pumped back up with return pump(s). That's it

 

[Len]

Man, I type slow. :lol: No, I have not bought the tank yet and yes I understand the use of gravity in an overflow system. But like I said, I'm not sure of the other "things" about them. How hard would it be to drill the tank, or is it just easier to get one with it already? Thanks.

Get one predrilled (any "reef ready" tank is predrilled with at least one drain hole, and some come with more holes to plumb your return through your overfow box if you prefer/specify). Drilling after the fact is problematic and hard to do for glass. Acrylic is easy.

 

[ReefRex]

Posted by Len

"Basically, you just need an overflow that can handle the flow of your return pump. So if the overflow is rated for 600gph, you need a return pump with less then 600gph at the output (you need to estimate head pressure loss from bends and height). Good thing is you can always throttle back the flow of a return pump with a ball or gate valve, so it's not really super critical."

Thanks Len. That's what I was looking for. I will look into the reef-ready tanks, but they are so much more expensive, but I guess you get what you pay for, right? Thanks again.

 

[ReefRex]

Get one predrilled (any "reef ready" tank is predrilled with at least one drain hole, and some come with more holes to plumb your return through your overfow box if you prefer/specify). Drilling after the fact is problematic and hard to do for glass. Acrylic is easy.

Are there any you would recomend? Man, you beat me to the punch every time. :lol:

 

[Len]

A reef-ready is really worth it. You don't want to stress over floods

Just about any glass manufacturer I know can make reef readys. All-glass, Oceanic, Aquarium Obsessed (in Canada where I got my tank), Interamerican, Glasscages .... those are the usual suspects.

 

[ReefRex]

A reef-ready is really worth it. You don't want to stress over floods

Just about any glass manufacturer I know can make reef readys. All-glass, Oceanic, Aquarium Obsessed (in Canada where I got my tank), Interamerican, Glasscages .... those are the usual suspects.

Cool, sounds good, thanks alot Len. Have a great New Year.