Microbubbles

[uryy4me]

I need some smart people to give me some suggestions. I just set up a new tank and I have a microbubble problem. I believe I have identified the source, but don't know how to fix it. The problem is that water entering the sump does not have time to settle out before being pumped out. The primary source of the heavy aeration is a 2" flex PVC line coming to the sump from the display and secondary/less significant contributor is a 2 beckett skimmer w/ air controls running wide open (doing this to drive CO2 levels as low as possible). I have been able to confirm that this is the source of the problem (vs small leak return lines lines) by temporarily correcting the problem. The solution that led to a temporary fix was to take an IO buck, cut a 4"x7" opening in the side of it, mount a section of egg crate to a 4" PVC pedestal that I could sit on the bottom of the IO bucket, then put a bunch of filterpads/fluff on top of the eggcrate and then direct the water from the display and skimmer over the pads through the egg crate and out the side of the bucket. The problem with this solution is that within a few hrs the bucket and filters get tossed around and the water starts to either overflow the bucket or bypasses the pads and then remains heavily aerated as it gets pushed back to the tank.

The standpipe design I have used is one that runs one standpipe in a 2" drain and the other 2" drain in my overflow is basically a backup in the event the standpipe clogs, it is an open ended pipe an inch or so above the overflow waterline. The overflow is ~ 24" long and the water level in it is ~ 3" below that in the display, water enters the overflow with quite a bit of force. In total I am pushing ~ 3800-4000 gph through this and down the 2" line.

My sump design is not ideal. It is a 150g stock tank (oval in shape). Water enters it from above (I should really consider getting a bulkhead for this) on one of the short ends of the tub. For various reasons due to space limitations I had to put the bulkhead that feeds the return pump in the center of one of the longer sides (vs. a more ideal location such as the opposite end of where water enters the tank.

I had thought about installing dividers into the tank but I don't know how to get these in place...measuring/installing would be tough now. I have played around with various configurations where I attempted to draw water into the sump from locations opposite water entering the sump and these did not work. So I am sort of looking to expand on the "IO bucket" solution and stumbled on to a Flow Basket. Seems to me this could work well assuming it has some sort of "blow off" valve that would allow water to escape if it became clogged such that it sould not handle the capacity (I would not want this to back things up in the display and overflow it).

Thoughts, other options?

TIA

- scott -

[uryy4me]

Anybody?

[Flatfish]

I had the same issue. Couple of things to try short of a redesign of the sump the goal here is to slow the bubbles:

First construct a chamber (a box) around the main drain into the sump. This could be a large tube or box with an open top and a hole in the bottom just bigger then the drain line. The bottom of the drain line should be a few inches above the bottom of the hole. The open top of the camber should extend above the surface of the sump. This forces the water out the bottom. The trick is suspending the box in the sump. I used an old hang on overflow box.

Next strap a filter bag around the end of the drain line so that the water entering the sump must flow through the bag. The bag and the drain line sit inside the above chamber. Tie the bag so that it will NOT settle on top of the hole on the bottle of the chamber. The bag will assist the bubbles in slowing and much of the air entering the sump will dissipate out the top of the chamber and only some will leave the bottom of the chamber. The bag will need to be cleaned often. Design it so removing and replacing the bag is not a pain.

Suspend the chamber so if it overflows, it does so inside the sump. I cut a notch in the top edge of mine.

This is pretty much the same thing at running the "flow basket" with a back and without the top so air can escape.

To get the rest of the bubbles out you’ll need to meter the flow of the water into the sump.

Might work, might not apply. Just thought I'd let you know.

Cheers!