and odd plumbing/pump/microbubbles question

[jacksonpt]

I've been having periodic problems with microbubbles in my display. First off, no... it's not from the drain or the skimmer - it's something else. Could the fitting on my return pump be every so slightly imperfect to the point where a VERY small amount of air could be pulled in, but it would not drip/leak?

FWIW, the pump is an Eheim 1262 that I'm running externally. I'm using the "correct" plumbing from the to the pump, but I didn't have the right stuff going from the pump back to the display, so I've got spa flex hose clamped to the outlet of the pump. I think that may be my issue.

 

[jansenwrasse]

Could it be cavitation is extremely common in the hobby

 

[jacksonpt]

Can you explain cavitation? I have this vague understanding of it because I've read about problems with cavitation before, but I'm not sure I've ever seen it explained.

 

[jansenwrasse]

when you create a vacuum the boiling point of water lowers significantly, so on the impellers the water would be boiling and the bubbles would not redissolve after leaving the pump (think about the bubbles behind a boat). So if you are restricting the intake of the pump or the tubing from the pump is not large enough the pump will cavitate. life reef sumps with the filter pad over the pump intake section are cavitation machines.

Hope this helps
Brian

 

[jacksonpt]

I think so, thanks Brian. I'm using the recommended 5/8" hose from the outlet, but could probably work something slightly larger. Unfortunately I can't go from the sump to the pump in a straight shot - there has to be a 90 in there. Maybe later in the week I'll drain the sump and see what I can figure out.

 

[jansenwrasse]

I would try to enlarge the tubing that has the 90 in it that could be the issue there could also be a small hole in the return tubing as well somewhere never hurts to check everything for something small before tearing apart the sump.

Im sure there are video's out there of water boiling at room temperature cool stuff

 

[pascal32]

can you use a piece of spa-flex PVC - it is availble at lowes in 3/4, 1", 1.5" and 2"

a smooth radius is a LOT less restriction than a 90 degree. Can be glued on like regular PVC

also watch the barb connectors and unions, most have a passageway onesize below what they are marked for.

I get bubbles from the drain into the sump. Double filter sock has helped tremendously!

 

[jacksonpt]

can you use a piece of spa-flex PVC - it is availble at lowes in 3/4, 1", 1.5" and 2"

a smooth radius is a LOT less restriction than a 90 degree. Can be glued on like regular PVC

No, I can't... not enough room. I'm trying to cram the enough equipment for a 65g tank under a 30.

also watch the barb connectors and unions, most have a passageway onesize below what they are marked for.

Ah, good call... forgot about that.

I get bubbles from the drain into the sump. Double filter sock has helped tremendously!

I know that's a common issue, but not in my situation.

 

[Gary Majchrzak]

if there's a strainer on the intake side of the pump remove it as they may cause micro bubbles

 

[jacksonpt]

if there's a strainer on the intake side of the pump remove it as they may cause micro bubbles

There is a length of 1" (I think, maybe bigger) PVC with slits cut in it, mostly to keep the macro out of the pump. Could that be an issue - it can easily be removed.

 

[Gary Majchrzak]

There is a length of 1" (I think, maybe bigger) PVC with slits cut in it, mostly to keep the macro out of the pump. Could that be an issue - it can easily be removed.

this could be the issue. Easy to find out.