We carry a Blast-It-Out kit which does a terrific job of backflushing jellyfish from a sea strainer--right back out the thru-hull. We've used it many times. The two most notable were when we were anchored off St. Tropez where we found our boat in a virtual sea of jellyfish and a few years later anchored in a gunkhole near the Lipscomb Lodge on the NE coast of Nova Scotia. Both times our generator shut down repeatedly due to a plethora of small jellyfish. With the Blast-It-Out, just close the seacock, remove the top of the sea strainer, select the right size "sealing stopper" for the opening, connect a garden hose with at least 35 PSI, hold the whole shebang in place, open the seacock, and turn on the water. The water pressure literally blasts the jellyfish pieces back out through the thru-hull. We're fortunate to have a fresh water system that runs at 65 PSI which makes the Blast-It-Out really effective, but less pressure will do the job too--just a bit slower. Blast-It-Out was designed and is marketed by a cruising couple. They don't take credit cards but they'll send the unit with an invoice and you can send 'em a check when you get it. Very easy to deal with. Here's the link, which shows how Blast-It-Out works and how to order: http://blastitout.com No connection with Blast-It-Out other than as a very satisfied customer. Milt Baker, Nordhavn 47 Bluewater, Rockland, ME