Purging Air from closed loops and locating air leaks??

[jlehigh]

I could use some help.. I have a few outlets plumbed over my tank on my closed loop with unions. I detach those outlets sometimes when I am working in the tank so air is sucked into the closed loop. When I re-attach the outlets and kick on the pump most of the air is blown out right away but I continue to see microbubbles for a long time. In fact I cant figure out if it's residual air from detaching and reattaching the outlets of if I am sucking air in from a different leak..

So the next question is.. what is a method to identify air leaks? I have one outlet with Salt creep at a threaded joint. It is so crusted I dont see how air could be sucked in but could it be?

Bottom line is I want my water to be clearer, but shoot... I can hardly even tell what is sediment and what are microbubbles!!! There is so much flow in the tank an air bubble may NEVER rise to the surface..

 

[Scooterman]

I use teflon tape on all threaded fittings, I use 4 or 5 complete wraps, this will seal most leaks, make sure you tape in the direction of the threads.

 

[jlehigh]

Thanks Scooty. Teflon is definately a must on threaded fittings. I did use teflon tape on my joints.. Well I am in the process of re-evaulating the placement of those over the tank outlets. I might move them down and to the sides. THEN comes the fun of drilling holes lower than the water level

anyone else have issues getting air purged out of there closed loop? btw my loop is driven by an ampmaster 4700.

 

[john]

bubbles

If the bubbles are going away after some time I don't think you would have leaks if it continues you probably have leaks the best seal on threaded fittings is clear silicone sealer, you could put a john guest valve at the highest point or point on the lines to burp the air

 

[Angelscrx]

I don't don't understand how to find the air leak? Do you have to take the whole thing apart and reseal with the teflon or silicone and then wait to see if you don't get bubbles? I see very fine micro bubbles in my tank and the only place I have teflon is where the pumps are connected. Everything else is PVC glue and no water leaks. By the way if you had a place that would suck in air wouldn't it shoot out water first? ( I know it's a strange question right?) Please clarify? Thanks

 

[john]

leaks

If the pipe was leaking on the inlet it would suck in air if it was leaking on the return it would blow out water if air was trapped in a high point in the return it could slowly blow bubbles until their was no longer any air in the system

 

[Hooked]

cavitation can also cause microbubbles

 

[Scooterman]

You should only have one location to fill the loop at the highest point, this will reduce most air trapped, that point needs to be taped and tightened the rest of the loop aside the two from the pump should be glued, if you have more then you can somehow submerge each connection until the micro-bubbles go away, then you will find your leak, however the problem is just that, trying to submerge the connection.

 

[jlehigh]

Some good stuff here. I have seen the John Guest valves used. Pretty cool! Weatherson over on reefcentral installed one to inject air through his line to better show the flow paths of eductors.

I am going to try to silicone a few joints though I think there is a good chance it is residual air..

Unfortunately my inlets are lower than 10 of the outlets. That wont change anytime soon. If you have seen my closed loop you can understand why modifications are major undertakings 14 outlets plumbed with rigid PVC and glued.

 

[jlehigh]

You know what.. now I am thinking I can remove the drum on my Oceans Motions unit as it IS the highest point in my closed loop. We'll see what happens. BTW: I am very pleased with my 8-way OM.

 

[Scooterman]

Cool info. on the OM!

 

[Angelscrx]

If the pipe was leaking on the inlet it would suck in air if it was leaking on the return it would blow out water if air was trapped in a high point in the return it could slowly blow bubbles until their was no longer any air in the system

Oh yeah makes sense duh!

So with cavitation is my pump actually too much for the plumbing, overflow, or what?