Little Help with overflow

[zenzence]

Hey everyone,
I recently purchased a AGA mega overflow. I have a mag 7 for my return pump which runs through a chiller before returning to the tank. Ok the problem is that the overflow isn't surface skimming and I can see a film building up on the surface. I have tried adjusting the stand pipe and adjusting air intake and I cant get the water level in the overflow to drop low enough to surface skim. I hope this make sense. What is the problem? Could the return flow be to low? The time it gets through the chiller and up to the tank the flow is minimal?

Idea's?

 

[sjm817]

Too low a flow wouldn't cause that. Usually, too much flow is the problem. Can you post pics?

 

[zenzence]

Ok I lowered the stand pipe even lower and now I am getting some surface skimming, however this created a new problem. Now the water level in the tank is too low (below the frame) how do I bring the water level in the tank back up while maintaining the current flow. Pics are a problem my cell doesnt take that great of pictures so I wont be able to show details of overflow.

Thanks sjm817

 

[scrager]

don't megaflows have like a bypass valve or door or something in the middle of the wall? if so is yours open? if it's open, then the water level in the overflow will always be the same as the water level in the tank. you want to close the valve so that the water flows over top of the overflow, skimming the surface.

this is just what it sounds like without pics.

 

[zenzence]

Nope no valve or door. anything else

thanks
scrager

 

[sjm817]

How big a tank is this? How much below the rim is the level? Where is the level on the overflow (outside)? A stronger pump would make the level rise.

 

[Fiziksgeek]

It might just be too little flow. The inlets down near the bottom and in the middle are designed to take in a small amount of water, with the rest going over the top. If you have really slow flow, it all goes through the lower inlets.

How much head pressure do you have other then the chiller?

If its like most tank..its probably 5 feet or so?Aand who knows how much the chiller ads.

 

[tptp279]

i would agree that it is too little flow, you have to give into consideration that mag 7 with 5 ft head alone is probably around 300-400 gph. now you have all the elbows and more line for the chiller so you are looking at probably around 200-300 gph. Is this the 90 in the description? another thing you can consider is getting some plastic and covering some of the lower holes so it skims the surface more. just watch it though. i know i currently set up a 90 AGA RR and i put a mag 12 with an aqualogic chiller inline and i don't believe there was any surface skim.

 

[ianward]

I would cover up the lower holes then play around with the drain height to see if you can get some surface skimming for now.
But it does sound like the pump isn't up to the task and the low flow into the tank is being handled by the lower holes so the top of the overflow isn't coming into play.
Just my 2 (2.5 Canadian) cents worth.

 

[zenzence]

hey thanks for the help! I believe you guys are correct. I may have to purchase a larger pump. Thanks for your help as usual