Having had a chance to look over the data from your table Mark. If you look at the TR140 sand filter with 2" multiport and compare it with the TR50 or 60 with 2" multiport, the additional filter media in a TR140 which holds nearly three times what a TR60 and even more than that in a TR50 yet it has the lowest headloss figures same thing with the TR100 so it isn't the filter media causing the headloss it's poor hydraulic design with the laterals. This is the area I am concentrating on at the moment.

Thanks again for the data.

Regards
John