Built in overflow question/problem

egill

egill

Member
I have a 240g with a built in overflow. It has 2 drains and 2 returns. They are in the same overflow in the center of the tank. I was doing some basic maintenance today and noticed only 1 of the drains is draining into my sump. I shut the system down and pulled the overflow tubes out and cleaned them up and when I did this water would drain from both with the tubes out. Now I put them back in and am still only getting 1 to drain.
Anyone have a solution to this?
 
E

eric b 125

Guest
what happens when you stop the flow from going into the 'working' overflow pipe? does the other one start working?
 
egill

egill

Member
Originally Posted by Eric B 125
http:///forum/post/3164268
what happens when you stop the flow from going into the 'working' overflow pipe? does the other one start working?

yeah, only one will drain at a time. I moved the overflow tube in a different direction and I'm getting at steedy trickle but the other drain is running full blast. Doesn't make sense to me.
 
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eric b 125

Guest
oh, okay that's great. what's going on is one of the pipes is creating a full siphon (the one running full blast) and the other one is just taking care of the rest. this is good for a few reasons. these setups tend to run quieter than just one standpipe and they also run smoother. once the first pipe purges all the air, there is literally no airbubbles or gurgling. also, should a snail or something get into the full siphon then the backup pipe will take over and will become a full siphon. if you ease back on your return pump so just the full siphon is running and theres nothing going into the 2nd, then should the first pipe get clogged, when the second pipe takes over the full siphon it will continue draining at the same rate and since there isnt a 3rd there wont be any eventual flood from the extra water the second pipe is currently allowing to trickle. i hope that makes sense. if it doesnt let me know and i'll try to better explain it.
 
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eric b 125

Guest
try completely blocking off the flow to the full siphon pipe with your hand and the second pipe should take over. it might take a minute for it to reach full steam because it has to purge the air that's in it, but in a few moments it should burp and start siphoning
 
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