Overflow Questions

[Salt Creep]

Seems like I never stop tinkering with this little 20 long reef of mine but I have made some changes and need some advice please.

I have had the tank drilled and I have a bulkhead in each back corner with 3/4" PVC extending up for my overflows.......I figure when the pipes are covered with purple they will blend right in and best of all they don't take up too much room. Question is what size pump should I get for return?? I have an 18 gallon Rubbermaid container for a sump which will give me approx 3-3.5ft of head working against the return pump. The overflows seem capable of handling a decent flow rate but I am afraid of getting a pump too large because a 20 long turns into a cyclone easily with too much current......plus I am using HD sand and too much current equals sandstorms!!! Is there any way I can tell exactly what flow rate those 2 3/4" pipes will handle??

Do you think the Durso mod is possible in this tank......doesn't sound loud on tests but ya never know.

Last question and I hope I say this right. I was thinking that I could possibly make this overflow silent but I'm not sure if it is possible?? Here is what I want to do. Can I cut the 2 pipes down about 2 inches below the top of the tank yet still get the water level up to the rim??? I would do this by having a return pump that was strong enough to overwhelm the pipes yet not overflow the tank thus making the pipe tops under water and silent and at the same time producing the max flow possible for the pipes. I hope that doesn't sound confusing.
The only downside I see is I may need a pump that will cause way too much current in such a small tank.

Thanks for any help.

The Magdrive 350gph should be about right
I am not sure if the Dursomod will work in this case.At any rate if using an open pipe drain you are asking for disaster by lowering the stand pipe in the water column. Efforts to balance the water flow will be pretty futile I think, if your stand pipe ends below the surface any appreciable degree

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I thought I was me, but we were wrong
email: geeflipr@internetcds.com

[gpohly]

Saltcreep,

You can get your standpipes silent w/ either the Durso mod or a slight change of the mod to get your water level up.

You probably won't be successful on overflowing the stand pipes and acheive a water balance. Even if you did, this would be so delicate that any debris plugging one of the pipes (say, a fish that died) would likely result in tank overflow until your sump was empty.

I use stand pipessimilar to your arrangement in my 50 with good success. I also am able to keep water levels close to the top of the tank AND keep it quiet with an arrangement that takes advantage of an underwater air intake. There are a couple of things you will need to change:

1. You won't be able to keep the standpipe 2" lower than the top of the tank. Instead, run the pipe to the top, and drill holes in the standpipe starting just below the level you want for your water. Drill enough holes in you pipe (I drilled 5/16" holes) to equal 1-1/2 times the area of your 3/4" pipe. (For a 3/4" PVC, this is 6 5/16" holes.)

2. Use a larger PVC adapter (I'd recommend a 1-1/2" x 3/4") slid down over the 3/4" pipe, and a 1-1/2" coupler on the adapter, so that the coupler essentially cups down over the holes you drilled in the standpipe. (This whole thing is roughly like a squared-off mushroom when you are done.)

3. Cap the end of the 3/4" PVC pipe, which will be above the adapter and above the water level, and drill a hole in the cap to keep the system from siphoning. Start with a small hole, 1/8" or so, and increase it if needed.

This arrangement will give you the high water level you want and quiet overflows. In my setup, I used a short piece of clear acrylic pipe instead of a coupler so I could see if something was trapped in the holes, but it isn't necessary.

Good luck.
Glenn

[RobP]

You were asking about what amount of flow you can expect through 2 - 3/4" tubes. I can't give you an exact but I have read articles where a guy used 2 - 1 1/2" holes as returns for a very large system. His sump return pump flowed 5000gph into the tank and the 2 return lines drained it with ease. From this we could say that 1 - 1 1/2" hole will safely drain 2500gph. It is also a given in mathematics that if you take a hole of a given size and change to 2 holes each half the size of the original you actually end up with more surface flow through the two than through the original one. Having said that I think you would have had more than enough flow through 1 - 3/4" tube. With 2 of them you may find the sound fairly non-existant simply because relative to their size not a ton of water will be gushing through them. I hope this didn't confuse you further.

Reefkeeper's tank is plumbed similar to mine, 2 1" bulkheads thru the back wall and it drains a MAg18 wide open, course it is noisy.
Just using the elbows with strainer on it, no boxed in overflow, surface skimmer arrangement

------------------
I thought I was me, but we were wrong
email: geeflipr@internetcds.com