Sump Issues/Why am I an idiot???

[bradejoe]

I have had my sump underneath my tank for about a year now and have occasionally had this problem. I don't understand why, and can't logic my way through the physics....

My tank and sump will be running in harmony and I'll notice my water level going down a little bit from normal evaporation. When I add water, the balance between my overflow and return pump seems to get out of whack and I end up with a mismatch of water level (i.e. My pump wants to overflow my tank). Doesn't matter if I add water while it is up and running or if I shut everything down and add water. Sometimes this mismatch happens and sometimes it doesn't. Always seems to happen when I don't have extra time to fool around with it.

Pipe diameters haven't changed, resistance hasn't changed, pump strength hasn't changed, overflow and "suction" the same... very frustrating... mostly because I don't know why. If I understood the problem, I'd be more okay with it. Anyone else run into this? Thoughts? Any and all insights would be appreciated.

 

[RyanCSGO]

what does your overflow plumbing look like? any pictures?

 

[Dsnakes]

I would recommend an ATO. That way once you see where to set your probes or float switch, there's no more need to worry about mismatched levels. Just fill the reservoir and let it do the job.

 

[bradejoe]

Sorry - I'm at work after a very frustrating lunch break "complication". I have a 46 gallon bow front with an Aqueon Proflex Sump below. I have an Eshopp's PF300 overflow box dropping down to the sump...and I'm pretty sure I have a Mag Drive pump, though I can't remember off the top of my head what the GPH is. Can always add pictures later.

 

[bradejoe]

May look into that...space is at a premium under my stand, unfortunately. And I'm open to that as an alternative - still just doesn't get me the "scientific explanation" of WHY it is happening.

 

[FugeReefer]

Is your drain pipe the same diameter as your return? Also, is there a valve on your drain?

 

[McArcher]

Why it's happening is the head condition changes when the level in your sump changes. Your pump will pump more when the level is higher. If your drain pipe is too small, the small change in flow might be causing your issue.

 

[TMB]

If I'm understanding you correctly your return flow increases with the relative water height in the sump? If so, this is normal. The reason is because the increased water level decreases the head pressure - resulting in increased flow. The reverse is also true - lower water level - less return flow. A couple inches of head pressure makes more difference than you might think when trying to tune a drain system.

The easy answer to the problem is as Dsnakes pointed out. Install an ATO - problem solved.

 

[bradejoe]

The overflow diameter is larger than the return pump diameter. And no I don't have a valve anywhere. Still a beginner and slowly upgrading things as I'm learning. And my wife just told me to get rid of the tank when she saw the dejected/frustrated look on my face. Sometimes taking it apart and tossing it seems like a good idea.

I hear what you guys are saying and starting to understand it a little more. Good news, I just "fixed" my problem. I accidentally bumped the U-Tube in the overflow box. This shifted the angle of the U-Tube (couldn't have been more than 2-3 degrees) and I heard a "whoosh" of increase flow down to the sump. Have been running it for about 30 minutes so far with an appropriate balance. Guess it was the angle of the tube causing the whole problem.

Sigh... Like I said in the heading...I'm an idiot.

 

[Donovan Joannes]

A very valid reason for a drilled overflow system...

 

[BluewaterLa]

Sometimes the hidden simple things right in front of our faces is the problem.
All too often we find ourselves presented with a problem and automatically start thinking of the most complex things to be the culprit or solution.
This happens quite a bit with technicians that have been around for a while, they start chasing all sorts of issues that dont exist looking for this elaborate issue/ problem and forget about the simple things to check first.
Only after chasing a ghost for a few hours they check the fuses and find that a fuse has blown, replace simple fuse and Bam, Problem solved.
I use this as an example quite often because it is human nature to start assuming the worse case possible and skip some of the more simple things that are usually the little things that bite us the hardest.

Glad you found your issue, the good thing is you wont soon forget to check this next time and could possibly save someone else from lots of frustration.
Good luck and happy Reefing
BluewaterLa/ Mike