Pump chamber size for external pump

[MikeInToronto]

Looking for some opinions. I'm converting a tank (48x18x20 lxwxh) into a basic 3 chamber sump per below.

http://gmacreef.com/wp-content/uploads/2014/08/sump-design-diagram-gmacreef.jpg

The pump is an external PanWorld 200PS, so 1750 gph (max). (Display is 72x24x30" if that's important).

I was wondering how large you think the pump chamber should be. I was going to go with 8x18x10". Haven't built a sump with an external pump in many years.

Thanks for any help/opinions!

[MikeInToronto]

Please also feel free to comment on the sizes of the other chambers. Or even a different sump design. My skimmer is 9.9 x 11.6 (Bubble Magus Curve A9 DC).

Thanks!

[Vinny Kreyling]

Mine is 2 sections because I wanted to use chaeto,
so its a 1' x 2' & a 3' x 2'
Many use Rubbermade tubs with no baffles.
Whatever works for you.

[thirsty saltine]

I wouldn't think it would need to be too big since its main function after the bubble trap would just be for holding water for evaporation and to get water to the external pump, so maybe 6 or seven inches so you can put some chaeto or something in there with the bulkhead to get to the pump.

[ca1ore]

It's really up to you. The advantage of a bigger return section is that it will 'last longer' before needing top off. Given the reliability of ATO units, this benefit is dubious;

[thirsty saltine]

agreed, a solid diy autotop off is super easy to do or just purchase one, I got mine from autotopoff.com and love it.

[MikeInToronto]

Thanks for all of the replies. My biggest concern is the amount of water that will flow through the chamber into the pump. I wonder about the amount of splashing. Maybe I'm over analyzing it.