sump and pump help

[carisma02uk]

hi all i have been designing my new set up for my 150gal and need some help on sorting out my pump size for my return to tank.
i will have a 5ft syphoned drop from tank to sump and then pumped from sump 5ft up to tank i need to know what size pump i will need cheers everyone JON>>

[ereefic]

What size are your overflows and how many of them? This will help recommend a pump for your application.

[carisma02uk]

it will be 2" pipe syphoned 5ft' drop from the tank to sump.

[Samper]

So there are no overflows per se only a siphon running up and over the rim of your tank and this siphon is 2" pvc yes?

[carisma02uk]

yes thats it.

[Reefland]

Hi carisma02uk, Welcome to Reefland!

If I understand this, you have 2" PVC in yout tank, running over the top that will siphon to your sump? If this is correct, it will never work. You can never get a straight siphon and a pump running water back to your tank to match flow rates and therefore will have a mess. You have to either use drilled internal overflows or an external overflow box.

[duster]

Hi Reefland. I too am planning a sump, but have never set one up before. I would prefer not to have anything hanging off the back of the tank, instead having all piping coming from drilled bulkhead fittings. However, you mentioned that a straight siphon supplying water to the sump (which is how I was going to do it) will not work. Why is this? Is it because a straight siphon either 1) doesn't supply enough water to match the pump or 2) supplies too much water and needs to be controlled? One of your recommendations was to use "drilled internal overflows". What exactly is this? I haven't heard of it/them and was wondering if you could expand on that. You already saved me from potentially piping my sump wrong, and now I'd like to know how to do it correctly.

[Reefland]

Here is a link to All Glass Aquariums that shows a diagram of a tank with an internal overflow with 2 holes drilled, one for the drain and the other for the return:
http://www.all-glass.com/products/aquariums/index.html

Basically with an overflow, the return pump pushes water from the sump to the tank, surface water drains into the overflow compartment with a standpipe that drains water to the sump. Now if you drilled the bottom of an aquarium and put a pipe in it, it would work the same but be loud and unsightly. Siphoning water from a siplay to a sump will not work because you could never get the flow from the siphon to match the return from the pump.

[duster]

Thanks Reefland. I remember looking at those All-Glass overflow designs before, but for some reason I didn't pay much attention and forgot about 'em. Now I see they are just about what I need. It is still somewhat of an intrustion, but it looks like a pretty clean setup. It looks like it blends into the back of the tank o.k. I had posted a thread before about a sump overflowing when the return pump shuts off (power outage). Do you know if the All-Glass system is setup to stop siphoning if the return pump shuts down?

[Reefland]

No they will drain somewhat. The overflows have grooves in the top of them and during an outage, the tank will drain to below the grooves, usually an inch of water from the display. Due to this, it's important to make sure that the operating level of your sump is low enough to accept any additional drained water with the return pump is off.

[duster]

I wouldn't think the water level dropping an inch or two will be a problem in a 55g main/20g sump setup, with the sump half full or less. I was reading another sump piping thread where it was mentioned that a check valve be used on the return line to prevent back siphoning. I understand the importance of check valves on "open" plumbing circuits where there is a second reservoir(sump) for water to drain into. But what about a "closed" plumbing circuit, like running a pipe from the main tank to a water pump (for additional circulation) and then back to the main? Would you put a check valve on this type of circuit? Also, how reliable are water check valves?