# 75+29g Sump DIY overflow Losing Siphon? Aqualifter?



## Wombatant (Sep 17, 2011)

Hello, i recently got my 75g aquarium with a 29g sump (3/4 full) running. im using 1" diameter DIY pvc overflow and a MAG 7 drive (3/4" return).

Im not sure why my system is losing siphon - several questions.
1. Does the bottom end of the siphon have to remain underwater in the sump all the time? Or will it only break siphon if it stops when not submerged (like if i do a water change and the water level drops below the pvc intake in the display tank)?
2. How would i use an aqualifter to maintain siphon? hook intake up to check valve on overflow (used to start siphon) and the out line just... in the sump?

thanks for any help!


----------



## metricliman (Sep 3, 2012)

So the tank is not drilled?


----------



## jchild40 (Mar 20, 2010)

Wombatant said:


> Hello, i recently got my 75g aquarium with a 29g sump (3/4 full) running. im using 1" diameter DIY pvc overflow and a MAG 7 drive (3/4" return).
> 
> Im not sure why my system is losing siphon - several questions.
> 1. Does the bottom end of the siphon have to remain underwater in the sump all the time? Or will it only break siphon if it stops when not submerged (like if i do a water change and the water level drops below the pvc intake in the display tank)?
> ...


Can you give us a pic of your siphon? You cannot allow air into the siphon when the pump is off. The opening won't be submerged.

Here are some examples of what I used to build my first siphon.

http://www.monsterfishkeepers.com/forum ... -Explained


----------



## jchild40 (Mar 20, 2010)

BTW: I have the same set up, a 75g with a 29g sump.


----------



## mel_cp6 (Feb 3, 2009)

We need to know which type of PVC overflow you're using to figure the problem. A pic would help a great deal. 
It most likely has an air leak if its constantly losing syphon. 
did u install a check valve?
It's also a good idea to only use about half of the sump when it's running so u have room when the power is off.

Btw, I've been using the exact same PVC overflow as jchild for a few yes now problem free.


----------



## mel_cp6 (Feb 3, 2009)

Btw, I always these PVC in pairs. If one fails, the other one can fully handle the pump flow. Thus limiting the chances of the pump flooding the tank.


----------



## jchild40 (Mar 20, 2010)

mel_cp6 said:


> Btw, I always these PVC in pairs. If one fails, the other one can fully handle the pump flow. Thus limiting the chances of the pump flooding the tank.


This is nice because if you were to put a ball valve on the first one, you can dial it in so it's nearly silent. You don't have to worry about overflowing because the second one will take the overflow.

I am using a overflow box now, it is a lot less intrusive.


----------

