why is my overflow flushing?

[celano]

I just installed a T, street ell and cap on my standpipe. Now my overflow is flushing like a toilet. The water level goes down about 2 inches then fills back up then goes down again....why?

 

[Satori]

Do you have a small hole drilled in the end cap?

 

[celano]

I drilled a hole then put an ajustable valve in and siliconed around it for a good seal. But no matter how I ajust the valve the stupid thing keeps flushing....

 

[catdoc]

I'd say you need a bigger hole drilled in it. You need more air coming in to break the siphon.

 

[celano]

<a href=showthread.php?s=&postid=9282726#post9282726 target=_blank>Originally posted</a> by catdoc
I'd say you need a bigger hole drilled in it. You need more air coming in to break the siphon.

I think you right. The more I watch it the more and more that makes sense.... Any idea what size hole to drill or is each setup different?

 

[jdieck]

Each setup is different, just drill with increasing drill bits until the surging stops.

 

[Satori]

My overflow pipe is 1.5", and my hole is 1/4". I drilled it through the side, through the cap and pipe so I could turn the cap to adjust the hole size.
Out of curiosity, is this already mixed with salt, or is it still the fresh water leak test?

 

[celano]

Thanks for all the help guys. Now off to the hardware store to get some more parts. Those guys know me on a first name basis now after setting this tank up...lol
Its been mixed now for about 4 days. I plan on starting the cycle after I get this plumbing figured out.

 

[celano]

Well after getting some more caps and drill bits and trying several different sizes with no sucess I went back to dursostandpipes.com and did a little more reading. It turns out the guy we bought the tank from used a 1" drain on a 1" bulkhead. Apparently this is a big no no....you need to go from 1" to 1 and 1/4" piping or it wont work right.
Sooo back to Ace I go to get the right size piping and fittings....

 

[Satori]

hmmm, my stand pipe is the same size as the bulkhead.

What do you have on the bottom (sump end) of the drain? A reverse durso helps with flushing, noise, and bubbles. In this pic you can see my 2. The one in the front is the fuge return, and the larger one in the back is the main tank drain.

 

[celano]

Nice setup MSM! What the heck is that tank for on the far right??

We just moved about a month ago and I cant find the camera yet so no pictures, but I'll explain my setup the best I can.
Alright, on the under side of the tank my drain line goes from 1" pvc to 1 and 1/2" pvc then through a ball valve, past a T and then into the skimmer part of the fuge. Next I have 3 baffles set inplace for a bubble trap, after that there is a 14" fuge area and finally another baffle with 1" holes drilled in the top. On the other side of this baffle is the housing area for the return pump. The return pump uses 3/4" pvc piping to return the water to the display tank.
Do you think the reason for the "flushing" action in the overflow is due to back preassure??
And sorry for the long description, but I want to give as many details as possible since no pics.....

 

[Satori]

That's my calcium reactor.
What happens when you take the cap off the durso?

 

[celano]

Calcium reactor huh? Sounds sweet!! I might get one of those oneday..in the distant future...lol What kinda corals you keeping to need one of those?
Anyway back on track. I just took the cap off and the standpipe and it makes this awful gurgling sound, but the water in the overflow doesnt go up and down anymore....Any ideas what the probelm might be?

 

[Satori]

Need a bigger hole in the cap?

 

[catdoc]

I put up with the sound of flowing water for a year after I set up my RR tank. I adjusted things here and there, finally decided it must just be b/c the water was falling so far (into the basement sump). Last week, it started flushing again so I got out the drill and a much larger bit, I roughly doubled the size of the hole. I should have done it long ago--I can barely hear water moving now! Doh!

My overflow output is under the water surface in the sump, btw.

 

[Rockitmakr]

Dude,
is your return under the water? If it is, you need to do a simple mod, put a T with one end facing up so that any air can & will be exausted.
:beer:

 

[Rockitmakr]

Upon further review of your pic......The T that you have is NOT installed right! You need to place it up & out of the water. Right idea, wrong location!
:beer:

 

[Satori]

<a href=showthread.php?s=&postid=9286986#post9286986 target=_blank>Originally posted</a> by Rockitmakr
Upon further review of your pic......The T that you have is NOT installed right! You need to place it up & out of the water. Right idea, wrong location!
:beer:

Do you mean my pic? Mine is the one that's working correctly.

 

[Rockitmakr]

Really????
I did exactly what you did & had a flushing effect, so I moved it up & out of the water. It works great now.....
The only other thing that I can think of that might be the culprit is that the overflow is not big enough to handle all of the water that celano is trying to run through it.
Sorry MSM, too much coffee this morning.
:beer:

 

[celano]

Just thought I would do a follow up for those interested or for those who do a search and find this thread.
Turns out that my return pump is WAY over rated for my overflow.
Its a Hydor pump rated for 900gph, after some more reading it turns out my overflow is only rated up to 600ghp. I dialed down my pump using the ball valve under the tank and now the overflow is working great. Just like it should be, no flushing.

I want to thank everyone that replied. Without your help I wouldnt have stuck with it and found the problem.
Thanks everyone!!