predrilled question

[morphviper]

I started to service a ladies tank today and her predrilled overflow was making all kinds of noise! so when I was looking at it someone glued an 180 elbow on it with a hole drilled in the top of the elbow (upside down U with one end in the line). I have messed with predrilled tanks for years and never seen anything like this. any clue to why someone did this.

I asked the lady that owned the tank and she said it was the last person who serviced her tank that did it. she doesn't know why?

 

[DeNero1331]

I would imagine the drilled hole is to prevent a siphon from forming. The only reason I could think of for the U at all is to either slow the flow rate or to prevent floating debris from going through the line...although, I could think of better ways to accomplish either result. Maybe someone else can come up with a better answer.

 

[fishfreek]

Sounds like a home made dorso stand pipe. The idea is that water will flow down the overflow quiter since its not sucking air plus the water level is higher in the overflow so its not splashing as much.

 

[morphviper]

Sounds like a home made dorso stand pipe. The idea is that water will flow down the overflow quiter since its not sucking air plus the water level is higher in the overflow so its not splashing as much.

This is what I was thinking too, but this is making a sucking sound and is gurgling. loud too. I figure that the whole in top was to stop a syphon but the didn't make since either, because the u shape is just two pvc 90 degree elbows glued together. that shoudn't create a syphon, but might create an air pocket so water won't flow through the drain and that is why the whole is on top.

why wouldn't you want to suck out the floating material? isn't that the whole point of the filter?

I have never seen anything like this?? crazy

I am open to any ideas as to why and if I should replace it and what with?

it is there for some reason.

 

[fishfreek]

http://www.dursostandpipes.com/

 

[DeNero1331]

Nevermind my siphon remark...thats for the return flow. The hole needs to be there to allow air to escape so the water can rise through.

I got it all sortsa backwards. Maybe the sound is being generated by too much water flow or too little airflow. If the air hole is too small the water flow will keep getting cut off as the air tries to vent. You should be able to check this by watching the water level in the overflow section. If it keeps going up and down then you know the exit flow of the water isn't consistent.

Hope that helps!!