Thread: Gravity retro drain using 40mm pipe?

HI All.

I am moving house soon and i've bought a 9000 litre steel frame pool to house my fish for about a year. I currently have a 4 bay cloverleaf filter which is pump fed pulling through a retro bottom drain.

The new pool is 1.2m high and I don't fancy lifting my huge filter up that high so i'd like to convert it to gravity fed. I was hoping to copy this retro bottom drain feeding through a bulkhead.
sg discharge via single 90 - 1.jpg

Question: Is 40mm pipe large enough to feed the filter via gravity? My pump is 12000lph.


Thanks

Will

Simple answer is no, 4inch or 110mm min

Originally Posted by Andymadd

Simple answer is no, 4inch or 110mm min

Dammit. I figured it would as I currently use 40mm pipe as a gravity return and that looks like it could handle 2x what is currently moving down it (approx 11k lph). Ok back to the drawing board. Thanks

Agree. Not a chance with 40mm. I think the image you posted uses 110mm but it does look smaller.