My pre-filter siphon keeps slowly breaking. Can't track down cause.

[shollis2814]

I'm not at home right now and my wife said my tank started overflowing. I think that my U-shaped siphon tube on my overflow has slowly started accumulating bubbles. I have rescued this situation once or twice before recently, but this tank is 4-years old and it has never given me this problem.

My return pump seems to be fine. My only thoughts are that perhaps the prefilter sponge is gunked up more than usual, slowing the overflowbox drain, which would allow the bubbles to accumulate, but I'm not seeing a difference in water level in the sump.

The other thing, and this doesn't make sense to me, but my prefilter box has an adjustable depth and it has slots that are wide on one side and narrow on the other to 'lock into place'. The last water change, I noticed the prefilter box was on the looser side, and I clicked it into place, which raised it up just a few mm.

I'm brainstorming here. Would love some thoughts as to how to track this down.

 

[FartyParty]

I'm not at home right now and my wife said my tank started overflowing. I think that my U-shaped siphon tube on my overflow has slowly started accumulating bubbles. I have rescued this situation once or twice before recently, but this tank is 4-years old and it has never given me this problem.

My return pump seems to be fine. My only thoughts are that perhaps the prefilter sponge is gunked up more than usual, slowing the overflowbox drain, which would allow the bubbles to accumulate, but I'm not seeing a difference in water level in the sump.

The other thing, and this doesn't make sense to me, but my prefilter box has an adjustable depth and it has slots that are wide on one side and narrow on the other to 'lock into place'. The last water change, I noticed the prefilter box was on the looser side, and I clicked it into place, which raised it up just a few mm.

I'm brainstorming here. Would love some thoughts as to how to track this down.

I used to have one of these for about 3 years on a euro-braced 65 gallon, but toward the end of that duration I had similar problems with siphon breaking and my house flooded. I will only buy "reef ready" going forward. Have you considered a gate valve to slow down the return in very small increments?

 

[shollis2814]

I used to have one of these for about 3 years on a euro-braced 65 gallon, but toward the end of that duration I had similar problems with siphon breaking and my house flooded. I will only buy "reef ready" going forward. Have you considered a gate valve to slow down the return in very small increments?

Thanks for your reply. I can't do reef ready right now, and I won't be able to do any upgrades until the fall. I'm trying to see if I can limp along for a few more months. I will look into a gate valve. I'm not familiar with it.

 

[JoshH]

What make is your overflow? You could very well be on the right track with your original thoughts with the choked up foam. And that's not something you would notice in your sump or DT's water level as the difference would be so small, fractions of a mm. You moving the overflow box up a couple mm could also have caused it as it changes the pressure the siphon has to work against which could make it easier for bubbles to form and stay in the top of the U pipe.

 

[shollis2814]

What make is your overflow? You could very well be on the right track with your original thoughts with the choked up foam. And that's not something you would notice in your sump or DT's water level as the difference would be so small, fractions of a mm. You moving the overflow box up a couple mm could also have caused it as it changes the pressure the siphon has to work against which could make it easier for bubbles to form and stay in the top of the U pipe.

It is an old ProClear/Seaclear sump with built in skimmer.
Thanks for that. I will give that sponge a good rinsing when I get home and watch it. I hate to change two variables at once, especially the prefilter box as that could affect my water levels in the sump and I would be in worse shape if the power went out.

Thank you again.

 

[JoshH]

It is an old ProClear/Seaclear sump with built in skimmer.
Thanks for that. I will give that sponge a good rinsing when I get home and watch it. I hate to change two variables at once, especially the prefilter box as that could affect my water levels in the sump and I would be in worse shape if the power went out.

Thank you again.

Not a problem. And that's a very smart plan, make one adjustment at a time and see how things work. It could be either or, or both. You just never know so best to take that route.

 

[paphater]

How close is your return pump matched to your overflow gph? I think if the water isn't moving at a fast enough velocity it allows the bubbles to stay at the top of the U. When I had my old life reef overflow box, bubbles would make in to the U tubes but would get carried out the other side.

 

[mcarroll]

I'd check your return flow too....slower flow can originate there too if an impeller is wearing out, etc. Either measure flow with a small container and a timer, or take your pump apart for a full inspection and cleaning – or better yet both, measure flow AND THEN do the maintenance.

(Lower flow, as you noted, will allow bubbles that might have washed right though before, to accumulate and ultimate start blocking flow altogether until the siphon breaks.)

 

[shollis2814]

It appears that both were the problem. I rinsed a lot of the sponge. It had some sort of micro organism that had built a lot of calcium shells further down and it was blocking flow. The 1-2 mm drop to the loose side of the bracket also increased the flow.

The bad news is that some of the water got into my Orbit LED controller....the LCD will come on, but the time is stuck at 00:08 and the remote no longer works. I have it in a bag of rice hoping for the best.

 

[TheEngineer]

A good backup is to put an aqualifter pump in your u tube. It will pull air out if it does break and help it get going again. It can safely pull either air or water.