ray
if you go back and actually read the question asked by allen he asked what size pipework would be recommended for a pond 2000/2500 gals which he was planning.
i said that as it was only this size it would be a good idea to step down as he would only need to turn over his pond at the rate of about 1000 to 1250 gals an hour through the filter.
now you can get a flow rate through gravity of 5000 gals per hour through a 4inch pipe and he is not aiming for that kind of flow rate so there is no need for that size of pipework
but i would not go any smaller than 3 inch because of the risk of blocking
and you would not be putting any more strain on your pump because all the pumps i use only have a 1 1/2 inlet and outlet with the exception of 1 of the sequence pumps which does have a 2in inlet
i have built maybe 100 ponds now as i do it for a living
and your on your first you do it how you want to do it and good luck to you
del
Posted on Jul 19, 2005, 8:27 AM from IP address 80.3.128.5