no really and emergence----- sump water levels

[beaslbob]

Our 90g tank runs for awhile (days), then starts spitting out air bubbles as the sump water level is below pump intake. Which is normal. And normally caused by evaporation.

System is a drilled tank with sump that drains to a drain section with filter sock, to a center skimmer/refugium section. over a baffle to the sump/return section. Under normal operation the baffle sets the center skimmer level at say 6" then the return section has a level of say 4" or so.

But what has me confused is we turn off the pump and the levels in the skimmer and sump sections rise several inches above the baffle with both sections the same level. Which actually is normal. But when I restart the pump the levels do not return to the previous levels but remain a couple of inches above the baffle.

So today I cleaned up the algae in the display return teeth before restarting the pump. I guess that could provide some blockage. And the sump level was above the baffle.

I think the levels not returning to previous running levels would mean that some blockage was 'cleared' by turning the pump off then back on.

Am I on the right track or is there something else I might check?

TIA

 

[Jon Fishman]

1). Get an ATO and not have to worry about evaporation affecting the level.

2). When pump is off, back-flow raises level, and it sounds like your drain-to-return pump ratio is affecting how fast the chambers are filled/emptied

3). how often are you turning off the return pump? I think I turned mine off in September once.....

 

[beaslbob]

Thanks for your reply

1). Get an ATO and not have to worry about evaporation affecting the level.

If it is a drain blockage the ATO would make it worse. By pumping water to the system, raising the display levels and possibly causing a flood. As opposed to just replacing evaporative water. that said I have designed and use an ATO in my FW tank and have thought about doing it for this tank.

2). When pump is off, back-flow raises level, and it sounds like your drain-to-return pump ratio is affecting how fast the chambers are filled/emptied

thanks. the problem is it appears the turning the pump back on does not result in the levels returning to the previous levels.

3). how often are you turning off the return pump? I think I turned mine off in September once.....

Several times per week for feedings.

 

[reefdad]

How large is the sump? Have you verified the flow rate back into the tank? Does the water ever return to the normal levels, even if it takes hours or a day?

 

[Jon Fishman]

How large is the sump? Have you verified the flow rate back into the tank? Does the water ever return to the normal levels, even if it takes hours or a day?

This is what I am thinking. Return rate from overflow/drain vs return pump are vastly different.

DC pump?? Is there any valves on the drain line(s)?

 

[beaslbob]

How large is the sump? Have you verified the flow rate back into the tank? Does the water ever return to the normal levels, even if it takes hours or a day?

Don't know the actual size of the sump. It is a commercial model about 3-4 feet long a foot deep and 2 foot or so tall. The sump area is the last 4-5 inches on the right side.

I don't think the levels return to previous power on levels after a few hours. Obviously even if from evaporation only they would return after days.
Haven't measured flow rate back to tank but the levels observed are constant. to the return and drain are matched.

 

[beaslbob]

This is what I am thinking. Return rate from overflow/drain vs return pump are vastly different.

DC pump?? Is there any valves on the drain line(s)?

the overflow return seem matched as the levels observed are constant. No valves anywhere. Drain is flexible tubing that came with sump.

 

[reefdad]

It sounds like the flow from your return pump is low. It may need a good cleaning or replacement. If it's a DC pump, you may be able to turn it up.

 

[Brew12]

the overflow return seem matched as the levels observed are constant. No valves anywhere. Drain is flexible tubing that came with sump.

Hey Bob, I've seen this a few times on peoples systems. Normally when this happens it is when the primary drain isn't flowing enough water. The overflow gradually fills over hours if not days, which makes the sump level lower more until level gets to the secondary or emergency drain, gains enough head pressure, or creates a full siphon depending on the setup.
When you turn your pump off, the overflow drains back into the sump causing level to rise. When you turn the pump back on, the slow process of gradually refilling the overflow begins again.

Let me know if that doesn't make sense. You may want to crack your drain valve open a tad and see if that fixes it.

 

[Brew12]

Sorry, just saw no drain valve... you do have 2 drains though, right? I suspect the primary is partially clogged so that it can't handle full flow anymore and causing level to rise to the 2nd drain. If you can clean that drain line it should help.

 

[reefdad]

I think a clogged primary would result in a lower level in the sump, since that's additional water volume that's stored elsewhere in the system.

 

[reefdad]

Oh, I missed part of the orginal post. Cleaning the teeth of the overflow could effectively lower the water volume in the main display (while running), so that could contribute to more water in the sump. I bet that's what you're seeing. The overflow/return balance has shifted. Remove water and watch your salinity. If they clog up again, and you add water as more water piles up in the display, your salinity will drop a bit.

 

[beaslbob]

Thanks Reefdan and brew12. I suspect it is some kind of blockage in the drain system. There is only one drain line a flexable tube type.

Will try keeping the display teeth free of algae and see if that corrects the problem. Otherwise will look for some kind of blockage in the tube itself.

I did buy a borescope last year for use with my phone. If I can find it perhaps I need to borescope the drain system.

Again thanks.

 

[RockyMountainReefing]

Thanks Reefdan and brew12. I suspect it is some kind of blockage in the drain system. There is only one drain line a flexable tube type.

Will try keeping the display teeth free of algae and see if that corrects the problem. Otherwise will look for some kind of blockage in the tube itself.

I did buy a borescope last year for use with my phone. If I can find it perhaps I need to borescope the drain system.

Again thanks.

Did u ever solve this issue