Sump Outlet Under Water ?

[nicky1200]

So i have bought a 6 x 2 x 2 fish tank a few months backand i have been trying to find some one who can supply fish safe pipe work now that  i have found some one i need to try and work out how to plumb in my sump. My tanks has a in built overflow but has 2 60mm holes for the bulk heads to go in. Here are some  images of what i mean.
 
This is the top of the over flow

 
 
Here is the bottom and mid of the over flow

 
 
 
So the big questions is how to plub it in... I have a out lut and a inlet in the overflow has you can see from the second pic. The problem i have is that the outlut needs to go up the overflow and out of the overflow over the top ??
 
I think i have 2 options the first option is to make the overflow fill all the time and make the outlut and inlet water stay in the overflow so the over flow will push water from the overflow down into my sump and then my pump in the sump will pump it back up into the over flow ( and not into the tank ). But im guessing this can not be done because that means the filters water will keep getting filtered ?  Or i can put a pip in side the bulkhead of the overflow so that the pump will pump the water from the sump thought the overflow though a pipe back into the tank but has you can see i have not much head room on the overflow and i think that the water level would make it so the pipe for the outlet would need to be under water ?

 

[DrRob]

Traditional is to run the return over the top of the overflow with a shepherds crook type affair and then outlet pointing away from the weir. Much like a return from an external filter would have to do anyway.
 
Personally I just use both pipes to feed the sump (reduces the risk of overflow if a pipe blocks and also allows you to play with ways to make it quiet) and return from the sump pump elsewhere, like any external would do.
 
Standard waste pipe is aquarium safe as well, although attaching it to some pumps and flexible hoses is a pain.

 

[nicky1200]

Traditional is to run the return over the top of the overflow with a shepherds crook type affair and then outlet pointing away from the weir. Much like a return from an external filter would have to do anyway.
 
Personally I just use both pipes to feed the sump (reduces the risk of overflow if a pipe blocks and also allows you to play with ways to make it quiet) and return from the sump pump elsewhere, like any external would do.
 
Standard waste pipe is aquarium safe as well, although attaching it to some pumps and flexible hoses is a pain.

But then i would be scared of the outlut from the pump falling out of the tank...
If you look how higher the overflow is to the glass surport  on each side of the overflow ( the first image )
I am guessing the outlut pipe would be under water ?If i put a pipe in the outlut bulkhead and then a t bit on the end of the pipe the t bit would be pointing out side of the tank .....
 
Also i couldn't find anyone selling bulkheads.... After 5 months of searchign and ringing around a found some one who sells them. I live in the uk and found us websites which sold them but was told by them the messurements in the us are metric and are diffrent from uk. Im gonna spend £100 on pipe work tomorrow for the overflow.

 

[DrRob]

http/www.cityirrigation.co.uk/acatalog/Metric-PVC-Tank-Connectors.html

 

[nicky1200]

http/www.cityirrigation.co.uk/acatalog/Metric-PVC-Tank-Connectors.html

 
 
Im using
http/cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=111122445971&ssPageName=ADME:RTQ:GB:1123
 
 
I just wanted to make sure i plumb it all in right. The bit im worryied about is the outlut being under water...

 

[DrRob]

uk and us do use slightly different measurements, you'll find that most will separate out imperial fittings and metric fittings. You also have to watch the difference between push fit, which you don't really want, and solvent weld, which is what you're after (the solvent seems to be fine).