Overflow Issues

[Anthrax15]

I bought a used cube that has a custom overflow. They never said what it was rated for.

Im running a RIO 3100 rated for 900GPH. Its not pushing out a ton of water at the returns. Also the overflow water level is above the overflow teeth.

What is going on?? I cant take out the standpipe because its PVC glued in place.

<a href="http://www.flickr.com/photos/anthrax15/9634340432/" title="Untitled by Anthrax15, on Flickr"><img src="http://farm8.staticflickr.com/7393/9634340432_d380dc670c.jpg" width="500" height="375" alt="Untitled"></a>

<a href="http://www.flickr.com/photos/anthrax15/9631102947/" title="Untitled by Anthrax15, on Flickr"><img src="http://farm4.staticflickr.com/3732/9631102947_53545ac794.jpg" width="375" height="500" alt="Untitled"></a>

<a href="http://www.flickr.com/photos/anthrax15/9631100893/" title="Untitled by Anthrax15, on Flickr"><img src="http://farm3.staticflickr.com/2833/9631100893_c970319978.jpg" width="375" height="500" alt="Untitled"></a>

 

[Anthrax15]

Is the inlet durso just too tall?

 

[sirreal63]

You are pushing more water than the drain can handle. What size is the drain plumbing from the bulkhead to the sump? A pic of that part would be helpful.

 

[Reefmedic79]

The water in the overflow is above the teeth? If the pics you posted are what it currently looks like the water level is fine.

It does look like the durso is a little high, but it won't effect performance. If the drain pipe is 1in. all the way to the sump you should be getting or handling around 500gph.

Your Rio is probably putting out less than 550gph @ I'm guess close to 4' of head w/ 3/4" pipe, not accounting for any elbows, couplings, or ball valves. Also, your head loss will be increased due to the reduction out of the pump, looks like 1/2" vinyl hose before the ball valve, and having 2 outlets on the return pipe.

 

[Anthrax15]

You are pushing more water than the drain can handle. What size is the drain plumbing from the bulkhead to the sump? A pic of that part would be helpful.

I'm pretty sure it's 1 1/2" diameter.

 

[sirreal63]

I don't see a problem if the pics are of it running. As reefmedic said, the pump is being restricted greatly. Are the pics of it running?

i am not seeing the problem.

 

[Anthrax15]

All the overflows I've had, water has cascaded down the overflow teeth. It's never been the same level as the DT water line. I didn't know if that was an issue.

If I just did a straight shot of vinyl with no ball valve and only used one return nozzle, ill get more return output correct?

 

[sirreal63]

It should not be a problem, as long as the flow is consistent, not flushing and not rising too high then it is ok. I always preferred a slight drop but the way it is is not a problem.

 

[Anthrax15]

If I just did a straight shot of vinyl with no ball valve and only used one return nozzle, ill get more return output correct?

 

[Anthrax15]

If I just chocked back the overflow a bit with a ballvalve, would this solve the surge of water pouring into the sump and lower the water level in the overflow?

I also am having an issue with microbubbles cause by the inlet.....

 

[sirreal63]

If I just did a straight shot of vinyl with no ball valve and only used one return nozzle, ill get more return output correct?

Marginally, if the plumbing is still the same size, in general terms to get better output from a magnetically driven pump, increase the output plumbing larger 1-2 sizes. However in this case you are already putting in too much water for the drain, see below.

If I just chocked back the overflow a bit with a ballvalve, would this solve the surge of water pouring into the sump and lower the water level in the overflow?

I also am having an issue with microbubbles cause by the inlet.....

Never put a valve or restriction on an open channel drain, very bad idea and will not correct anything. If the drain is flushing they you are putting in too much water to the drain. Use a valve on the pump output to limit the water entering the drain, this will stop the flushing and help smooth the flow.

 

[dkeller_nc]

Just for the record (Sirreal is precisely correct that upping the water output of the pump isn't going to help), the biggest restriction in your return pump output is the elbow and Loc-line returns to your tank. An open ball valve is nearly a straight-shot of pipe - it doesn't add much to the overall flow restriction.

Regarding the drain configuration, this is my speculation: The original designer hated the sound of falling water, so he sacrificed getting a lot of flow through the overflow for dead-silent operation. Specifically, the drain is set up so that the water level in the overflow is nearly at the tank's water level. That greatly reduces falling-water noise, but also cuts down on the overflow capacity a good bit.

If you want more flow through the overflow, you could lower the drain plumbing by an inch or so. That will ensure that the flow through the overflow teeth is the maximum that can be had without removing the whole thing and adding one that has more teeth (and therefore more area between the teeth for water to flow over the overflow).

 

[Anthrax15]

So basically, the overflow is fine how it is. More flow=bigger pump. I think I'll just stick with the one I have and add an extra powerhead.

Regarding the sump, the overflow surges through the sump causing a bucketload of microbubbles. Is there anything I can do to reduce this? I dont like running filter socks so that would be out.

Any suggestions?

 

[sirreal63]

Close the ball valve on the return a little until the drain operates without surging. A gate valve works much better here than a ball valve but you should be able to tune it close enough with the ball valve.

 

[Anthrax15]

How would closing the ball valve on the return do anything for the overflow inlet into the sump? The return is already putting out low flow.

 

[sirreal63]

If you are getting surges down the drain, it is an imbalance of air and water, also known as flushing and the only real solution is to reduce the amount of water being fed to the drain and the way to do that is to reduce flow from the pump.

 

[Anthrax15]

Sorry, I worded that wrong. I did mean surge like a toilet, I mean there is just a ton of water coming into the sump constantly causing lots of microbubbles.

That is what Im wondering if there is anything I can do to reduce this. I absolutely hate microbubbles.

 

[sirreal63]

The answer remains the same, slow the flow down.

 

[Anthrax15]

Slowing the flow down in the return wouldnt do anything. It would slow the flow of the sump water but not the water coming in from the overflow.

 

[sirreal63]

Yes it will, the same gph coming out of the return in the tank is the same gph that goes into the overflow, it only drains out what is going in. Slowing the flow from the return also slows what enters the drain system. If your tank is not operating that way then it is in a different reality from the rest of this world. What goes in is what comes out unless there is a restriction, then there would be an overflow. Pushing more water through an air assisted drain than it can adequately handle causes flushing and excessive micro-bubbles. I wish it were not a reality, but it is a reality.