Closed loop causing many micro bubbles

One_Divided · #1 11-15-2003, 07:19 PM

I was just thinking the other day how I've never had trouble with micro bubbles.. Well of course after installing my closed loop, my tank is fulll of them.. I'm not sure what is the cuase since there is no air being sucked in at all. It is a mag 5 going through a squid with two 1/2" returns. Both sides blow very fine bubbles..

Anyone have any suggestions as to what might be cuasing them?

thanks in advance,

-Adam

Buccaneer · #2 11-15-2003, 10:38 PM

One possible cause would be cavitation in the pump either from too much or too little back pressure ... the squid may be causing it as it opens and closes from one output to the other. HTH

Cheers

One_Divided · #3 11-16-2003, 10:10 PM

hmm I don't think it could be that since I had the squid plumbed in to my return before and had no problems with bubbles. the output plumbing was all the same too.

The only I have noticed is that the pump is slightly leaky around the seal.. I tightened the screws, but it still leaks a little.. maybe it is sucking a bit of air in through the pump? I guess I will silicon around it and see if that solves anything..

Anyone else have any ideas? I am getting really frusterated on this!

Son Of Skyline · #4 11-16-2003, 11:51 PM

Quote:

Originally Posted by One_Divided

The only I have noticed is that the pump is slightly leaky around the seal.. I tightened the screws, but it still leaks a little.. maybe it is sucking a bit of air in through the pump? I guess I will silicon around it and see if that solves anything..

That's gotta be it. If the closed loop isn't drawing air straight from the intake (sucking sound) then it's gotta be a leak somewhere. The air's gotta come from somewhere.

Good luck!

Buccaneer · #5 11-17-2003, 12:16 AM

I hope you did find the source of air input but I am here to tell you that I have personally had cavitation on a 4MDQX by using 2 X 1" outputs and had microbubles and by changing to a single 1" output it eliminated them altogether ... do a search on cavitation or microbubbles if you dont believe me on RC or elsewhere ( something about high pressure and low pressure freeing up air bubbles in the water )

Cheers

One_Divided · #6 11-17-2003, 12:42 AM

ok thanks rasta.. Hopefully I can make this work as I orginally intended.

Scales · #7 11-17-2003, 09:59 PM

I have had problems with cavitation on all the mag pumps on my systems (2 - 12's and an 18). Input flow restraint was remedied by placing the two 12's in the sumps. Even so, I still have problems with one mag 12 which must be throttled back (output) a bit to prevent micro-bubbles. At full open, it sounds like "rattling screws" and spits out bubbles. I have tested for leaks and can find no evidence of any (the pump itself and the housing connections are submerged). The mag 18 isn't causing problems currently...it is on a closed loop with a 1 1/4" input reduced right before the housing to prevent input restriction...the output is theoretically restricted from the initial 1" to approxiamtely 1/2 (it used to go through a squid which was removed after it failed to "switch").