Return Overflow Protection?

[kreebog]

Hey there - new to the forums. I've started my reef tank about 15 months ago and it's been quite an adventure and a wonderful (if sometimes heartbreaking) learning experience.

About three months ago I replaced my canister filter with a 20g sump via a HOB overflow box - so far so good as far as far as filtration goes, but I've had several overflows. One time it was because the siphon break on the return nozzle was clogged and I was able to fix that by adding a check valve, but the three or four other times were caused by the display tank flooding due to mysterious slowness in of the overflow feeding the sump.

I have not been able to figure out what causes the overflow to stop being able to keep up with the return from the sump - I've tested it with the pump running full-bore (~1000gph) and the overflow keeps up fine, but I normally run it at ~450gph... It just sometimes doesn't keep up. Everything is clean, the siphon in the overflow is solid... it's a mystery to me.

In any case, I wanted to install a water level sensor in the display tank to kill the return pump if the water rises to the rim, but I have been unable to find anything that will do the job for me. I tried rigging up a JBJ ATO system, but it seems that most ATOs don't like to run continuously so that didn't work out.

Any suggestions?

Thanks!

 

[theMeat]

What type/brand hob overflow?
What size drain pipe?
Is it a straight run down?
What return pump?

 

[pecan2phat]

If your placement is within clear glass then you can use this to shut down the return pump. I use it in a skimmer overflow unit.

AUTOAQUA

www.autoaqua.com.tw

 

[Clarkjw2002]

Probably getting air bubble build up in the overflow tube. Depending on what you have, this can happen at slower flows--especially if bubbles are making their way into the tube.

The flooding tank suggests you either don't have an appropriately sized sump (which I'm guessing you do w/ 450gph return) or you don't have an isolated return chamber (and/or not enough excess capacity in the display).

The return pump should be in a section where water stops filling it if the main sump level drops an inch or two. This is achieved by a divider that tops out an inch or so below the normal sump water level. I'd burn out a pump before I ever overflowed a display. If this is not the issue then maybe your water level in the tank is too close to the top of the tank? Drop the overflow box in the tank some to lower the water level and give you more cushion if this is the case.

Siphon break cleaning should become part of your normal maintenance routine. When I've run systems with holes as breaks I've always checked them at least weekly at feeding time.

 

[kreebog]

Sorry - I meant to include more info:

Overflow: EShopps PF-800
Tank: 55g tempered glass (hence the overflow)
Sump: 20g, 4 sections
Skimmer: Aqua-V EV-180

I don't have any trouble with bubbles making it to the return. The 3/4" ID overflow hose has a pretty good drop, but does level out a bit before dropping again into the sump. I'm not hearing any gurgling or anything and the flow is fine 99% of the time. The water level stays stable even when I test it at ~1000gph.

Last time it happened I wondered if the return hose was getting blocked or something so I dismantled everything and cleaned it, but there was nothing in there.

Thanks for the tip about Autoaqua, @pecan2phat - I'll check that one out.

@Clarkjw2002 - I don't think things are sized quite right... I can't get the sump and tank balanced to where the sump runs dry before the tank overflows unless I leave a couple of inches of space in the display which just looks crappy IMO. I've been running it that way since the last overflow while I look for an auto-shutoff solution.

 

[theMeat]

Post a pic of the sump layout

 

[kreebog]

Here you go @theMeat - kind of messy right now, but cleanup is this weekend

 

[Clarkjw2002]

Kinda hard to tell the direction of flow but I think the blue pump is your return.

Is that the normal running level? If so your dividers are completely non-functional right now. The water level at the sump should be at the level of the top of the dividers (just overflowing the one before the return) in the main chamber and lower than the top of the divider in the return section. You should be able to remove water from the sump down to these levels without affecting the tank level. Adjust the return to maintain appropriately. That will solve the display overflow issue probably--unless you have no excess capacity at all in the display.

On the overflow, if no bubbles, then it shouldn't randomly slow down unless your filter sponges are getting clogged. These do need cleaned weekly (I'm assuming you have the sponge before the overflow line to the sump installed?). It's possible you have a snail or something in the actual line to the sump below the HOB box as well. This could cause issues too.

For these HOBs I've always liked to run two for redundancy (or one with two overflow tubes and two lines to the sump). Stuff does get in there from time to time.

 

[theMeat]

Here you go @theMeat - kind of messy right now, but cleanup is this weekend

You want the first section from tank the highest. This should drain down to your second section. Then there should be a bubble trap of sorts to your final, lowest section where your return pump is. This final section is what fluctuates with evap. Something like this

 

[kreebog]

The blue pump feeds the skimmer in the middle chamber - the larger, silver pump on the right side of the sump is the return. A second HOB would give me some piece of mind if I can't get an overflow sensor setup to work right, though.

Good tip about the dividers - that makes sense. I think the skimmer is a little too big and it forces me to run the feed pump too fast for this size of sump so I end up adding water to keep the pump from sucking that first chamber dry, but I just didn't think about the baffles needing to actually control flow

It looks like I have the flow direction right according to the image - my return pump is after the bubble trap / baffles.

I did check the HOB boxes and lines for obstructions, but everything was clear. You're right about stuff finding it's way in there though... I once found a peppermint shrimp trapped in the filter sock! Luckily the little guy survived his misadventure.

 

[theMeat]

The blue pump feeds the skimmer in the middle chamber - the larger, silver pump on the right side of the sump is the return. A second HOB would give me some piece of mind if I can't get an overflow sensor setup to work right, though.

Good tip about the dividers - that makes sense. I think the skimmer is a little too big and it forces me to run the feed pump too fast for this size of sump so I end up adding water to keep the pump from sucking that first chamber dry, but I just didn't think about the baffles needing to actually control flow

It looks like I have the flow direction right according to the image - my return pump is after the bubble trap / baffles.

I did check the HOB boxes and lines for obstructions, but everything was clear. You're right about stuff finding it's way in there though... I once found a peppermint shrimp trapped in the filter sock! Luckily the little guy survived his misadventure.

Getting a second hob is a mistake. You need enough flow through the u-tube in order to not get an air bubble that stops the siphon. Your hob is capable of 800gph, that’s enough. Also don’t think your issue is the drain pipe is getting clogged. More likely the foam pad on the top of the pipe. Would get rid of that and make a diy stockman standpipe to help with noise

 

[gbroadbridge]

Sorry - I meant to include more info:

Overflow: EShopps PF-800
Tank: 55g tempered glass (hence the overflow)
Sump: 20g, 4 sections
Skimmer: Aqua-V EV-180

I don't have any trouble with bubbles making it to the return. The 3/4" ID overflow hose has a pretty good drop, but does level out a bit before dropping again into the sump. I'm not hearing any gurgling or anything and the flow is fine 99% of the time. The water level stays stable even when I test it at ~1000gph.

Last time it happened I wondered if the return hose was getting blocked or something so I dismantled everything and cleaned it, but there was nothing in there.

Thanks for the tip about Autoaqua, @pecan2phat - I'll check that one out.

@Clarkjw2002 - I don't think things are sized quite right... I can't get the sump and tank balanced to where the sump runs dry before the tank overflows unless I leave a couple of inches of space in the display which just looks crappy IMO. I've been running it that way since the last overflow while I look for an auto-shutoff solution.

I'm not sure how close you're running the water level compared to the rim of the tank, but 1.5 - 2 inches is quite normal

 

[Clarkjw2002]

If I were using a HOB for a 55 I'd do two 300s, not 2 800s. The 800 is already too much for the tank.

If a peppermint shrimp got down your overflow line then I assume you are not using the sponge pre-filter. This is for preventing stuff like this from happening--not for reducing noise. I would use and get an extra so you can swap out weekly and clean on your own time. I did this for years w/ a double HOB on a 125 w/out issue.

To reduce noise (if that is an issue for you) stick an airline hose down the overflow drain. Insert slowly until you find the point where the gurgling noise is most reduced. Once you find it, secure the airline and keep it there. This acts as an air escape vent and will significantly reduce the noise.

A stockman standpipe is a great idea. These did not exist when I ran HOBs (or at least I was unaware of them).

If it were me, I'd replace the 800 w/ the 300s, making stockman standpipes for both, and rebuild my sump baffles as per the illustration above. Believe this would solve all issues provided your 55 water level is an inch or so from the top of the tank..

 

[Projects with Sam]

Hey there - new to the forums. I've started my reef tank about 15 months ago and it's been quite an adventure and a wonderful (if sometimes heartbreaking) learning experience.

About three months ago I replaced my canister filter with a 20g sump via a HOB overflow box - so far so good as far as far as filtration goes, but I've had several overflows. One time it was because the siphon break on the return nozzle was clogged and I was able to fix that by adding a check valve, but the three or four other times were caused by the display tank flooding due to mysterious slowness in of the overflow feeding the sump.

I have not been able to figure out what causes the overflow to stop being able to keep up with the return from the sump - I've tested it with the pump running full-bore (~1000gph) and the overflow keeps up fine, but I normally run it at ~450gph... It just sometimes doesn't keep up. Everything is clean, the siphon in the overflow is solid... it's a mystery to me.

In any case, I wanted to install a water level sensor in the display tank to kill the return pump if the water rises to the rim, but I have been unable to find anything that will do the job for me. I tried rigging up a JBJ ATO system, but it seems that most ATOs don't like to run continuously so that didn't work out.

Any suggestions?

Thanks!

If you take the float off and turn it around you convert the float switch from normally closed to normally open.
that should let you use your ATO fix.