Originally Posted by stevehaun
I do 35 gallon batches and use an 809. I would like something faster. That said, if you are using a herms or rims, I think you will get grain bed compaction if you jack up the flow very high.
On any of these pumps you will need to use a grant or restrict flow to avoid compaction, IMO.
To the OP:
I have a March with the high flow options (also known as 815) as well as an LG TE-5.5-MD-HC and it moves a lot of wort. That said, I would be fine with the 815 for my 20 gal batches. I can get a whirlpool going with either despite the restriction in the line of recirculating the wort through my CFC as I whirlpool.
If all your lines and ports are 1/2", you're going to be hard pressed to do much better than a hi flow 809/815 and every incremental gain in flow rate is going to cost you significantly more $$$.