How to "FINE TUNE" Megaflow overflow

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holdendaniel

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i have a 55 gal DT single overflow(aga megaflow) it has spaflex straight down to the skimmer section....when operating the water level in overflow box keeps going up and down multiple inches/when it does that it shoots lots of air bubbles(chuging) tough the tube in skimmer water....please help i have tried priming system adjusting drain tube(in overflow box, aswell as in sump setup


anyhelp plz
 
Does it have an adjustable air inlet at the top?
I drilled mine so an air tube would fit, then adjust the length that the airtube runs down the overflow until the flushing stops, leave an inch or so at the top.
I think the airtube runs about 6 inches down the pipe toward the sump in my setup.
 
I love these threads, so much information on the how too's and resolve issues.....I didnt have that issue.
but I will go on to say I LOATHE PVC ball valves...fine tuning is a PIA with a valve that wont turn, wont turn then Bam it turns a 1/4 turn when your trying to get that fine tuned flow. ( I am NOW aware of gate valves LOL)
 
I also run Spaflex, with a Megaflow overflow. If I have too sharp of a bend, in the spaflex, I get a chugging and flushing problem. At the same time, the water level in the overflows, fluctuates in time to the flushing. When I straighten out a bend, even just slightly, and it quiets down and solves the problem.
 
my spa flex is a straight piece down. just curious how far do you put it under the water, do you ever put it horizontal with the water?
 
IME, the problem you are experiencing is due to your return pump producing higher GPH than your overflow can handle.

If your return pump has any type of valve to adjust the flow, I would try dialing that down. Otherwise, the solution I used was to install a ball valve between the return pump and the display. If I open the ball valve past a certain point, I get a lot of gurgling like you've described. But if adjusted correctly then all is good.

HTH & good luck!

Rob
 
my friend has a 125 we are assembling right now he is using the ehiem 1262 (has two overflow on tank) and his is gurgling as well i was told the overflow should beable to do like 1200 gph i believe? i dont know why i should have to throttle down my retutn?
 
Have a look at the durso design...
I had that issue on the cold water tank, adding air into the pipe keeps it from flushing.
The "herbie method" is indeed dead silent, but you need two holes.
Just make a durso quick and give it a test, I think it will solve the issue :)
 
my friend has a 125 we are assembling right now he is using the ehiem 1262 (has two overflow on tank) and his is gurgling as well i was told the overflow should beable to do like 1200 gph i believe? i dont know why i should have to throttle down my retutn?

For your friends tank if you want to get rid of the gurgling all together and you have two drains then simply run one as a true siphon straight to the sump. This would be a line where the intake and the exhaust of the drain are both completely submerged. The other drain is used as the emergency drain also going straight to the sump for just in case the first one gets plugged by a roaming snail or something. I cut the return line on this one a couple of inches above the water level of the sump. This way if this drain is being used I hear the splashing of the water falling into the sump and I know I need to adjust things a bit. Doing all this you will need to dial down either the drain or the return line from the pump because their flow rates have to exactly match each other. In my case my pump can't keep up with a full flowing drain so I close the valve partially on the drain until the water in my overflow holds a steady level thus matching the drain and return flow rates. If you have a pump that will out-perform your drain gph then you would simply open the drain all the way and then dial back the pump. I believe the best way to do this is to install a "T" in the return line above the pump with either ball valves or, better yet, gate valves on both outputs of the "T". this way when you dial back the return line you can relieve the pressure that is restricted from going to the tank out the "T" and return it to the sump to be cycled again. This keeps any back pressure off your return pump and should help it last longer and make less noise. I am a firm believer in this method even though this is our first tank. We have it in the dining room and it is totally silent. I think our refrigerator is making more noise and its 20 feet away (or maybe we just need a new fridge :)) Naw, I'd rather upgrade some equipment than spend money on appliances and luckily the wife agrees (for now).
 

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