Overflow box problems

Mattyice008 · Sep 3, 2013

So I have a CPR overflow box, forgot the model but its the one rated for 1200gph. It has worked great for a straight year, and last week at work my mom texted me saying there was a problem with the tank. So I raced home and found that the overflow box wasn't draining water. I cleaned the tubes, air pump that starts the siphon or water was fine, but it wasn't draining water. So I manually sucked the air through the tube from the nipple at the top, and it started draining again. So now it works, but every other day I see that I'm starting to have the problem again, it doesn't drain as much as it used to, and the return pump section in the sump has a lot less water than there should be..like there's no way it evaporates that fast, the overflow just isn't draining as much or something. There's no blockage, no leaks, it all looks fine. Anyone else have experience with this problem?

Reefing Madness · Sep 3, 2013

Do you have the air lines in the overflows properly? If your pump isn't pulling the air out of the top line there, then it won't start the siphon, Id say something may be in the line, such as possibly salt creep, I get that once in awhile. I also check my airlines once in awhile and adjust as needed. Are your leveling screws intact? Vibration from the tank move them? Is the intake side still sufficiently under water?

Mattyice008 · Sep 3, 2013

Yea I checked all that

Reefing Madness · Sep 3, 2013

Something stuck in the overflow lines themselves? Snails perhaps from the Sump?

VB68 · Sep 3, 2013

How about the pump - try putting putting the output end under water and the input side out, so that it draws air. Is it bubbling? I have had mine actually reverse flow,usually when something had gotten in the pump. I would un hook it, run a bowl of vinager water thru it or use a pipe cleaner to clean out what ever is blocking it.
This has happened to me 3 times. I now have the prefilter on it and have had on problem since. I also have a new spare pump just in case.