Overflow Issues

[Anthrax15]

Did the pictures help at all?

[NTP66]

What sirreal said is the easiest solution to a common problem. Put a valve on the return to slow the rate going into the drain, and the surging and microbubbles all go away.

[dkeller_nc]

Based on your pictures you don't have the option of installing a ball valve on the overflow outlet to the sump, as you have no emergency standpipe. However, you can still install a PVC overflow baffle as described earlier. Yes, if you want to look at it that way, the construction I described could be visualized as a constantly overflowing filter sock.

[Anthrax15]

What would be the best way to put the very large 1 1/2" rigid tubing in the larger PVC? Also what size would be adequate? 3" or 4" PVC?

[Anthrax15]

Bump

[dkeller_nc]

Originally Posted by Anthrax15

What would be the best way to put the very large 1 1/2" rigid tubing in the larger PVC? Also what size would be adequate? 3" or 4" PVC?

The PVC for the bubble baffle is going to need to be at least 4-6" in diameter. You want the slowest, thinnest film of water overflowing completely around the perimeter that you can get. BTW - It may be necessary to have this PVC professionally cut, or at least cut on a miter saw, because it must be absolutely straight up and down when mounted in your sump. Otherwise, the flow will be only on one side instead of the whole perimeter, which will greatly reduce its effectiveness.

The reinforced flex tubing that you have probably can't be bent to go in such a device. You will either have to hard-plumb the drain, or turn the sump completely around in the stand so that it enters the correct chamber without having to be forced over a baffle as in your picture.

[Anthrax15]

Alright so here is what I have so far. I was able to find an attachment and make a 90 degree bend so the tubing would go in the PVC bubble baffle. The PVC diameter is 4". Im just waiting for the silicon to dry for the bubble baffle and I will test it out.

Anything I need to fix or change? I will be running a piece of PVC down the inlet tubing so it goes to the bottom of the bubble baffle. How high does the bubble baffle need to be with the water level? Above, at, or below the water level?

Inlet:



Bubble baffle before I cut it down:

[dkeller_nc]

It needs to be well above the water level. What you're trying to do is to get a thin film of water to overflow the PVC tube baffle. That film will contain bubbles, which will break as they travel down that thin film of water.

Essentially, what you're doing is the same thing as a triple-baffle setup in a traditional sump. One advantage to the PVC pipe baffle design is that it can be moved around the sump and/or removed if necessary.

[Anthrax15]

How much higher? A couple inches?

[Anthrax15]

So I installed the bubble baffle and we are still getting microbubbles in the DT. It's driving me crazy!





Microbubbles in DT:

[dkeller_nc]

You may not be able to completely eliminate the micro-bubbles, but you should be able to get close.

A couple of other suggestions:

Drill about a 1/8" hole in the top of the elbow of your fitting that goes into the bubble baffle. That should allow some of the entrained air in the drain to escape before it gets flushed into the baffle, mixed with air and creates lots of little bubbles. The upper part of the drain fitting in the overflow should also have a small hole in it - this is the essence of the Durso drain design.

Make sure that you're working on the piece of equipment that's causing you the grief - skimmers are known for putting out micro-bubbles, and they can usually be fixed by adding a foam sleeve to the output of the skimmer.

Also, realize that if the only thing you've got in the tank at this point is saltwater, you're going to have way more bubbles than when you've added live rock and sand. It's counter-intuitive, because the LR and critters produce the waste that creates the foam in the skimmer, but I can tell you first hand that there's a big difference between a saltwater-only tank (particularly new saltwater) and one that's been stocked.

Buy a ball valve (or better, a gate valve) and put it on the output of your return pump. How much air you entrain going over the overflow and into the drain sensitively depends on the flowrate. You may be able to dial back the flowrate by 20% and make a huge difference with the bubble baffle (that's what Sirreal was suggesting).

There's really no reason to have a large amount of flow going through your sump with modern set-ups and propeller pumps inside the tank. You really only need 3-5 times the system volume going through the sump per hour.

Finally, if you've taken the above steps and still cannot dial it in the way you want, you're going to have to install a triple-baffle in your sump. While more involved than the PVC pipe bubble baffle, it's still not all that hard. The drawback to doing it, though, is that you must remove the sump, empty it, dry it completely, clean the inside glass where you're going to install the triple baffle with acetone to ensure a good glue bond, use aquarium-safe silicone, and allow it to cure for a minimum of 24 hours.

If you go this last route, you've a choice - you can make the triple baffle out of glass, or acrylic, or both. Cutting acrylic is easy, glass, not so much. If you want to go with glass, you can usually get a glass-specialty shop to cut the pieces you require out of scrap. It may be even less expensive to go to a full-service hardware store like Ace and get them to cut window glass to your specifications. For acrylic, most cities have an acrylic & fiberglass specialty supply house. Many of these stores sell their off-cuts for cheap to students in the design school at a local University.

[Anthrax15]

Thanks for the help everyone! Especially dkeller_nc! Ended up dialing down the return along with adding the bubble baffle cured my issue. Ill just throw another MP10 for the extra flow.

[sirreal63]

It was the answer all along. Glad you got it working.

[Anthrax15]

Lol thanks to you too sirreal63

[dkeller_nc]

Glad you got it fixed. Bubble elimination can be pretty aggravating.

[sirreal63]

High flow with an open air drain works better with a larger sump, that 20 high doesn't give much room for bubble dissipation before the return picks them back up and send them to the display.

[Av8bluewater]

Durso pipe is too high. Simple as that. That overflow box looks really tight on space but I guess nothing wrong with that. That plumbing should not be glued in. Should be threaded at the bottom and slip ons up top that you just wiggle tight. If you lower it it will probably get a better siphon. Probably getting air in it that high up.

[Av8bluewater]

If he did it right try to wiggle the top parts loose.. to see if they come off.
If they come off easy get a slip to slip coupling for about $.73 at Home Depot and shorten the pipe a couple inches.