closed loop micro bubbles

[mofrags]

I have a closed loop with oceans motions super squirt with a sequence pump and revolutions that spin to 3 of the 4 ports at a time and I am getting all these microbubbles from where I can not figure out. no leaks, my intake is 15 inches under water so no air intake there. someone was suggesting that my hose size was to large on the returns. I find if i turn off 2 of the four ports I don't get nearly as many bubbles. I ordered a 1,2,3,4 port drum to see if this would help? has anyone had this happen?

[samtheman]

Search on line for the explanation of cavitation. That is probably what is causing your bubbles and it is probably due to an oversized pump for the conditions and plumbing. You can reduce it by using a valve to reduce the pump output.

[seaskraP]

if your using loc line for the returns they can sometimes leak a little air.

also, the OM cannot handle all the flow from most sequences w/out either a valve to reduce the flow, as mentioned, or a separate output plumbed before the OM (also needs a valve).

[skerz]

i encountered the same problem w/ my snapper/supersquirt...as seaskrap post..i plumbed a valved bypass which reduced flow and eliminated microbubbles

[demonsp]

If its a new setup then it will take some time to break in and stop.

[samtheman]

<a href=showthread.php?s=&postid=12093544#post12093544 target=_blank>Originally posted</a> by demonsp
If its a new setup then it will take some time to break in and stop.

Why is that?

[AZDesertRat]

What is the size and length of the plumbing both suction and discharge? How many fittings are in the suction side?
Is it drilled or up and over?
Do you have a ball valve on the discharge you can squeeze down to test bubble output?

[mofrags]

I got the problem taken care of I got a one port drum and tuned down the ball valves and no more cavitation thanks. I have a 1.5 intake in middle back, it runs to the garage down about 7 feet and back up. branched to 1" returns reduced to 3/4 revolutions at tank I thought the 1.5 would be enough intake to be fine but if I was to do it again I would have put in 2 x 1.5" in a tee to the input. in my next dream tank I will have all external overflows and external closed loop boxes with bigger returns

[dots]

"Entrainment" is what you probably have. As my very knowlegable Wastewater industry peer AZDesertRat was eluding to, he was going to check if your NPSH and NPSHA are in the region to cause cavitation.

Most of our problems are air entrainment from tank discharges picking up the entrained air or air leaks in fittings.

You will know cavitation when you hear it.