Everyone with overflows/sumps?

There isnt much you can do with the overflow box itself. To get more watermovement near the bottom you can either adjust the return to output towards the bottom, or even add a powerhead to each tank (something small like a Mini-Jet 202)

As for overflows themselves, get one with a U-tube, you do not want a continous syphon like the CPR

Vortex (the Diaotom filter folks) used to make a constant-level siphon with an adjustable external standpipe - the internal pickup tubes were comparable to large canister intakes (or actually identical to the large Vortex Diatom intakes). These would do what you want if they are still made - I've been using mine for many years without problems.

I customized my skimmer box for just that reason: I wanted the skimmer to grab debris from the bottom of the tank (as well as the top).

I cut a hole in the side of the skimmer box (1" x 1") and epoxied a plastic pipe to it (it's actually the extension tubes for an Emperor 400). I have the bottom of the tube about 2" above the sand layer.

Now, the skimmer box grabs from the surface and the bottom.

This picture shows it a little:




EDIT: Just thought I'd throw in some technicals in case you do this:

Make the hole near the top of the skimmer box. Bear in mind that the lowest point of the hole is going to be how low your water will go when you shut off the pump (and that water will go into your sump, so make certain it has the capacity to handle it).

??? why not? Without the continous-siphon style you run into serious issues with power outages (which do happen often enough around here!) and the siphon draining the tank too much, then not restarting when the power comes back on and your return pump kicks in again!

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I meant dont use an overflow that uses a weir. Use an overflow that has a U-tube.

Excuse my ignorance but, what is a weir?

My overflow does not have the U tube. It is the "continuous siphon", I assume (as that is what Amiracle calls it). I have been told (and witnessed myself) that air will eventually gather in the bridge over time due to the splashing of the water into the skimmer box causing some air bubbles to get sucked into the bridge. Then, you need to suck it out with the air-tube attached to the one-way valve on the top of the bridge.

However, I made an egg crate shelf in the skimmer box for a filter pad (1st step of mechanical filtration) and this stops all air bubbles from shooting down with the turbulence and getting sucked into the bridge.

I have literally turned off my w/d only about 5 times in the past 7 months for projects. Other than that, it has been running continuously (even when I change the pads) and I have never had any air build-up in the bridge.

Just an FYI if air build-up is the concern regarding these skimmer boxes.


Side note: I think CPR has the "continuous siphon" overflows WITH the skimmer box that is VERY skinny (the box that sits inside the tank). It would be very inconvenient to set-up the filter pad shelf idea in one of these. Thus, these could be very prone and notorious to air build-up problems in the bridges that could cause loss of siphon. >> That would be a nightmare! Maybe your reference is in comparison to these units.


The Amiracle "continuous siphon" overflow has a large skimmer box. I forgot the dimensions, but, I use a Fluval 4 Plus foam pad (on the egg crate shelf I installed for the 1st step mechanical filtration) and it just tightly fits.

Originally posted by SamsonNY
Excuse my ignorance but, what is a weir?

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exactly what your talking about, the sort of bent over tube that creates a siphon.

My overflow does not have the U tube. It is the "continuous siphon", I assume (as that is what Amiracle calls it). I have been told (and witnessed myself) that air will eventually gather in the bridge over time due to the splashing of the water into the skimmer box causing some air bubbles to get sucked into the bridge. Then, you need to suck it out with the air-tube attached to the one-way valve on the top of the bridge.

Click to expand...

The bubbles are a major problem. Any overflow that needs a powerhead to suck out bubbles has a problem right from the start. Its a disaster waiting to happen. The powerhead might fail, or the tubing might get a crack in it... etc etc.

I hear you. Mine definitely had that problem at the beginning. I was sucking air out of the bridge about once a week.

But, the egg crate shelf w/ filter pad idea fixed that problem.

Like I said, just an FYI for anyone with a similar set-up.