Doing some research on the lowest head loss for a large capacity quad cartridge filter. I plan to replace my undersized StaRite. I was going to go Jandy CV580 until I compared the specs to other brands. Attached are the flow rates from the companies filter manuals.
The Waterways doesn't have a curve but states "Maximum head loss @ 150 GPM is 4.1psi", which is the lowest head loss if the manufacturers are using the same parameters in their testing. Jandy shows the highest head loss.
From the charts at 80 GPM head loss:
Jandy 5 psi
Pentair 2.5 psi
Hayward 3 psi
At 150 GPM:
Jandy off the chart - est to ~14-15psi
Pentair ~7 psi
Hayward ~10 psi
Waterways 4.1 psi
What is interesting is that Jandy states the CV (Versa plumbing) increases efficiancy, but both the CV and CL are rated the same on their curve.
Waterways indicates they use 2.1" internal plumbing vs others that use 2".
I was not able to find specs on the porisity of the filter medium used by the different manufactures. Differences would effect flow rate as well.
[attachment=0:s7vt4lmg]Quad Filter comparison.pdf[/attachment:s7vt4lmg]