HELP! Where's my water going!?!

[Phyber]

I have a Marineland CornerFlow 65g tank, and have been noticing that the water level in the main display has been going down, so much so, that the water never flows over the top surface skimmer comb. Water continues to flow under/through the mid level comb and then rises over the partition, but never over the top.

Baffled, I tried a few steps...

1. Thinking that my return nozzles were too low, I raised them. No increase in water level.
2. Thinking that my return pipe could be clogged, I totally drained the overflow and removed all piping (including durso's, return pump, and downpipe). I washed them all out and found no significant cloggage.
3. Repositioned my ATO sensor level. I run a Tunze Osmo that hasnt skipped a beat. This didn't help either

As you can see, I'm grabbing straws and out of ideas. I have also verified that:

• The tank is sitting completely level
• There are no leaks of seals or sump
• The overflow is not leaking. When it was drained, it held water fine
• No power heads are shooting water out of the tank
• My skimmer is pulling gunk (I skim wet) but my ATO is keeping up fine

Water used to be firmly in range of the black trim but now is about 1/4" below at all times. Where is the water going? Please help!

 

[skinz78]

Can you post a pic?

 

[ritter6788]

Can you post a pic or video of what you're saying? I'm not picturing it.

 

[palvyre]

You have a leak into the overflow somewhere. The lower comb doesn't actually go into the overflow. It flows up the wall and then into the top overflow. If your water level is not getting to the top then you have a crack or leak somewhere between the tank and overflow.

 

[Phyber]

Here are some quick pics. You can see the gap of water and that there is no flow over the upper comb of the overflow

You can see in the last pic that the water is just BARELY touching the lower opening of the combs. There is definitely no water going over.

I suspected the overflow is leaking, but I had the overflow empty for over an hour with no leakage (no more water was added into the overflow; I had the level marked with tape).

 

[palvyre]

If the leak was in the overflow itself between the bottom and top comb that test wouldn't catch it.

 

[Phyber]

I don't follow...let me elaborate....I turned my return pump off, then removed my downpipe, causing all the water in the overflow to drain to the sump. I then removed the return up pipe and began my cleaning procedure. During that time, there was no stream/trickle/drip of water coming in from the display tank. Completely dry.How would I determine where the leak would be in the overflow? The tank was purchased new about 9 months ago and the overflow isn't damaged.

 

[skinz78]

You're drain pipe should have a slip fitting that allows you to raise it higher, have you tried this?

 

[redfishbluefish]

You're drain pipe should have a slip fitting that allows you to raise it higher, have you tried this?

+1

The durso style downflow pipe is too low.

 

[impur]

+2 The top of the durso elbow is barely at the bottom of the top combs. The water level in the overflow will not go any higher than about mid level of the top durso fittings

 

[ecam]

How strong is ur return pump. The overflow maybe faster than the return.... leaving all the water in the sump and not in the return... Also i have a simlar tank setup... and i have my mid level flow closed off. u may ant to close the middle

 

[WesF]

Water can't drain to the sump at a faster rate than you pump it in. Water just "spills" down the drain at the rate you pump it to the display.

 

[Phyber]

thanks for the advice guys, i'll take a look at my downpipe level tonight and fidget with it.

I run a Mag 5 return pump. I chose low flow sump to go with my skimmer. The pump has never had issues maintaining any water level/rate...just recently. I disassembled it, cleaned with vinegar, and put it back in action as good as new.

How would i be able to block off the middle "intake"?

 

[Phyber]

Quick update:

Came home and messed with the downpipe. I tried all different heights but the water never came over the top comb. I do have a slip fitting but it was glued since tank setup to both the bulkhead fitting and downpipe. This hasn't changed. How high should my durso's elbow be?

I am noticing that the return pump output doesn't seem as strong as it used to...it has been cleaned inside and out. How could reduced output do this? I believe my MJ900 is putting out more water

Again, prior to noticing this problem, I altered nothing about the tank. Literally just happened to notice one night that my top comb was bone dry and water hadn't been going over it.

 

[redfishbluefish]

A MAG 5 is not a “pressure†pump and probably is only putting out something like 250 gph. Input your plumbing layout in THIS head loss calculator to calculate you pump output. Your problem might just be that you’re only putting a little water “in,†and that is why you’re only getting a little water “out.â€

 

[Phyber]

thanks for the link to the form. after entering in the data is still says i should be at 294gph.

This problem hasn't been occurring until recently; when the pump/tank was new it all worked fine. Now...the level is down and I notice the return nozzles are trickling out water.

Should I be looking into a bigger return pump?

 

[Dave3112]

Sounds like the impeller shaft of the mag 5 may be cracked. Thats the one thing I hate about Mag pumps. I have broken countless impellers cleaning them.

 

[Phyber]

hmmm...I did clean the inside of the pump recently...i made sure to be careful not to damage the shaft/impeller....

is there a common place that it would break at?

 

[Dave3112]

Mine usually break right beneath the rubber grommet on the top of the impeller.

 

[chrispc66]

You can do two things, assuming all is well with the return pump. Use 1/4 round around the bottom of your hood to hide the water line, or blank off a section at the the bottom half of your comb. This will lift the level of water in your tank.

I like to have a bit of room between the top edge of the tank and the water level, added security.....I would go for a hood mod myself to hide the water line.

Good luck and your set up is nice and neat by the way...