cpr overflow

[postalj]

If anyone has any experience with a CPR overflow I could use some help. I cant seem to get the noise (air being sucked down the overflow every couple of seconds) to stop. It is rated at 600 gph and the return pump is a viaaqua 4900 with a ball valve to control the return. Does any have any mods or experience in silencing this thing or is that the way they usually operate. The sump is a 29 gallon with baffles and the main display is a 72 gallon bow front.

[Cove Beach]

Hi i have a CPR overflow on my 75. There are several causes to your noise problem.
1.) drains need to be no more than 2" below the water level in your sump.
2.) You may be restricting the return line and the overflow is running out of water. (try opening the valve all the way)
3.) If #2 didn't make the noise quit than your return pump can't keep up with the overflow. From here you have 2 choices, one is to put valves on your drains, or get a pump that will keep up. You can always throttle the output of the pump back if you have to. Also depending on how restrictive your return plumbing is you may have to look at that also. Good luck!!

[Mighty Dread]

The overflow should have come with a little straw like tube that sticks up out of the drain strainer. You can use the rubber o-ring to adjust the height of the "straw". Usually you can adjust this and cut back the noise quite a bit. Try different hieghts until you find the setting that produces the least noise. It worked for me.

[Racing1]

I agree with mighty dread. Use the tubing that goes in the strainer to adjust it. Also how much head loss are you allowing for the pump. Also, Never put valves on your drain line. That is an absolute overflow problem down the line. You either need a pump that can keep up with the overflow or adjust it the best you can to quiet it down. I run the cpr cs50 on my 29g with a mag5 return with 3ft of head and have almost no noise whatsoever....