Posted by Janet Christian on June 26, 2006 at 19:42:40:
In Reply to: need advice for husband posted byApril on June 26, 2006 at 14:54:27:
But not as well as a pond filter. Pool filters are designed so water enters at the top, pours down through sand, and exits the bottom. Pond filters are designed so water enters in a series of pipes at the bottom, "boils" (velocity-wise) up through suspended filter media, and exits the top.
Pond filters are MUCH more efficient at filtering organic-laden water and providing lots of oxygen for the muck-eating bacteria. But be prepared for less filtration than you thought you'd get and for more frequent backwash requirements.
I would definitely not use the pool skimmer -- it isn't designed at all for organic water. The tiny basket mesh will clog with algae on a regular basis.
I'd also avoid the pool pump. They are designed for high-volume, high-pressure flow. The following is from a good friend who is an expert at this sort of thing:
Swimming pool pumps are made more for driving a highly-restrictive DE or cartridge filter system, so they're designed to push far more pressure than most koi-pond filter systems need (or can stand). As you stated, they're expensive to run on a gallon-per-gallon basis. Other than that, they're just pumps like any other pump.
In a pinch you could use a swimming pool pump to drive a koipond if you must, but you need to do two things:
1). Check the amp draw. Most swimming pool pumps are designed to push (hard) against a restrictive flow path. If you run some of these at the low heads of a koi pond filtration system, you can burn them up. Most are designed to run with some back-pressure. Check the amp draw "as-installed" and make sure it's not pulling more than the nameplate. If it is, throttle it back on the outlet until the draw is within spec.
2). Arrange a bypass or pop-off valve such that under NO condition wil the pump drive the filter system beyond it's design limitations. (I've seen pictures of a large bead filter which was subjected to 70 PSI. The top separated and went-off radially like a bomb. All those beads turned into shrapnel. If anyone would have been standing near it, they would have been seriously injured.)