<blockquote id="quote"><font size="1" face="Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by cookgraygoose</i>I have sent emails out trying to find out more information on the pump as you suggested. It is old and I don't know if the company archives will show up the information requested or not but I am hoping to hear something from them.<hr height="1" noshade id="quote"></blockquote id="quote"></font id="quote">You want to measure actual pump performance, since you might have a worn, underperforming pump. Here's a page about using a ruler to measure the drop from the end of an open pipe, and matching it to a table, to get a flow rate
http://extension.oregonstate.edu/catalog/html/ec/ec1369/
As for reworking the lawn sprinklers, you'd probably be happiest with Maxipaw impact heads, if you have to run on dirty water. Not the first choice for clean city water, but very good for pumped pond water, on the lower pressures from pumps.