Need More Input on Overflow Design

[apache73]

Hello Fellas,

I have uploaded a couple of pics illustrating my design for an overflow/return system for an Oceanic 37 cube. Currently, I plan on having one overflow hole drilled for a 1” overflow. The return has one hole drilled for ¾ inch bulkhead and PVC. The return pump will be an Eheim 1250 pump with. The expected return will operated somewhere in the neighborhood of 250 gph.

The guy who built the internal overflow told me that the projected flow rate going through my overflow, the sump, and return plumbing will be low enough so that a durso or stockman pipe will not be needed. He suggested just simply attaching a strainer to the top of the elbow within the internal overflow (see picture), and that the noise would be negligible.

OK, let’s say I design this system this way and later discover that it is indeed noisy and I decide to go ahead and install a durso anyway. My main question is where would be the best place to drill the return? Either over or under the dursopipe is what I am trying to decide on. My picture illustrates the return coming from underneath the durso. I would like to install the return so that it’s as high as possible with respect to the waterline within the tank so that if there is a power loss the amount of possible water siphoning would be lowest by running the return plumbing over the durso if it’s installed.

Bottom line, what would be your preference? Mount the return plumbing through the tank and overflow either above or below the durso system? The reason for the return going through the internal overflow is for aesthetics and simplicity.

Thanks,

G
http://reefcentral.com/gallery/data/500/126453Back-View.jpg http://reefcentral.com/gallery/data/500/126453Front-View.jpg

[Danyal]

you might try adding a pair of 90deg elbows inside the overflow, it will enable you to make the hole higher or you could drill a hole in the top of the tank(if it's acrylic) and put an L shaped peice of PVC going into the tank at the heigth you want. or even more simple would be to put a one way check valve somewhere between the pump and return, you'd loose even less desplay water that way(decreasing the risk of sump overflowing) because the water will simply not flow back into the sump through the return line, the durso stand pipe would drain the tank a little but your sump should have enought to handle that encase of a power out.

[apache73]

Bump

[apache73]

Anybody else have suggestions to my questions?

Thanks,
G

[jimmyj7090]

I would not do it the way it's shown in the pic - the return hole is way low, it would need a check valve (highly unreliable in SW, do not use check valvles IMO).

How about just adding a bracket to the inside of the overflow to hold a return line over the top without drilling at all. Add a short section of locline to direct the flow (with the outlet just below the surface).

[apache73]

OK, then mounted above the durso as I suggested as an alternative then?

G

[BeanAnimal]

WHy not drill the overflow hole near the top and build an overflow shelf the entire lenght of the tank. You will get FAR better surface skimming. Lose the teeth, they are useless. With 250 GPH and an overflow the width of the tank, the water going over the weir will be a very thin sheet.

Return over the top or through the overflow at the top. I am not sure what you are going to use for flow.. but a 37 is pretty darn small to cram PHs into. A single closed loop with an oceans motions returning over the top would be ideal.

[Z-Man07]

stay clear of the check valves!!! in time they will fail!!!

You have to take the time to plan a good plumbing system with a large enough sump that you will not need to rely on a check valve. Which will fail!!!!

Jay

[apache73]

BeanAnimal,

Thanks for your response as well as everybody else.

The overflow that is shown is the actual one going in the tank. It's already been built.

I don't want to be punching alot of holes in the tank and I am trying to apply the KISS theory as much as much as possible when it comes to flow within the tank.

When they hit the market, I plan to use 1 to 2 6025 Tunze nanostreams in the tank.

So, the question remains the return plumbing; over or under the durso-if a durso is needed. The pictures illustrate the plumbing going under. I understand the need to minimize the amount of water syphoned in the event of a power outtage. Hence, I am leaning towards going over a durso if I later choose to install one.

Thanks,

G