I have a closed loop running with a mag7 on it causing alot of bubbles. Checked everything and I know it's the closed loop. I am not using any sponge on the intake for the mag7, just a homemade strainer. I am running two 90's to get up and over tank, then one more leading to pump, all 1 inch pvc. Then a reducer to go to the mag7 which is 1/2 inch. Then coming out I go back up to 1 inch from the 1/2. I have checked all the glued sections and covered them in silicone, so I don't think there is any air being sucked in. I have read alot about cavitation and was wondering if there was a way to check to see if that is whats causing the problem. Maybe I should have the pump lower behind the tank? Right now all the elbows are connected right next to each other with no straight lines.
closed loop
- Thread starter jspot
- Start date
If your pump is at least 6" below the intake from the tank and the line size is at least one size larger than the connection to the inlet of the pump you shouldn't be experiencing cavitation. Sounds like you have done your homework there.
If you have a valve on the discharge you could try throttling the pump back to the point that the bubbles stop, just for giggles and maybe some information.
Good luck.
If you have a valve on the discharge you could try throttling the pump back to the point that the bubbles stop, just for giggles and maybe some information.
Good luck.
CoolUsername
New member
If you can't see bubbles going into the intake and they are coming out of the output. There must be a place where air is getting in. Try closing the output while it's running (maybe with your hand covering the outlet to build up pressure in the system. This will help you detect a leak in the section between the pump and the outlet. The air intake would likely leak water out instead of suck in air under the higher pressure and lower flow.
The section from the intake to the pump is going to be harder. It may be the pump itself I heard of MAG's leaking. They are not supposed to be recommended for external use (although lot's of people use them successfully)
The section from the intake to the pump is going to be harder. It may be the pump itself I heard of MAG's leaking. They are not supposed to be recommended for external use (although lot's of people use them successfully)
Sounds like I should move the pump down a bit. Right now it is sitting higher or right at the level of the intake inside the tank. Would lowering it by adding a length of pvc after the first 2 elbows coming up and over the tank lip help me out? I have pulled the loop off and siliconed each joint, so I really don't think any air is being pulled in.
Man this sounds fishy to me. I agree with Coolusername's method for checking for leaks on the discharge but in reality if there is a leak big enough to let air in, I think water would leak out of it when the pump is turned off.
USUALLY, cavitation occurs only on higher powered pumps but I suppose it's possible.
I hope that minds supperior to mine can chime in here cause if those tests don't help in solving your problem I am stumped.
