Install waste shut off valve or replace spider gasket

[riegal]

Nine months ago I replaced the spider gasket in the multiport valve. It leaks when backwashing. When I was researching how to replace a spider gasket I seem to remember reading some advice that said it would be better to install a shut off valve in the waste line and use that when backwashing. It seems that spider gaskets are problematic & frequently leak.

Is doing that, installing a waste line shutoff valve instead of replacing the spider gasket advisable? Would possibly affect the pool filter operation?

Also, when I checked the valve there was sand in the valve compartment of the multiport valve. Is this indicative of other problems with the valve?

Thank you.

[Larry]

Hi Riegal

It sounds like the sand is wearing out the gasket and this should be addressed first. Possible reasons for sand in the multiport valve are:

• a broken or damaged collector at the bottom of the filter
• low sand level in the filter (with side mount valves)
• clumping or calcification of filter sand
• short feeder/ diffuser pipe (with side mount valves).

To overcome the problem of water loss through the waste line on older filters, we sometimes install a valve on the waste line and have noticed no problems as a result. However, one must always remember that a worn gasket may cause a small percentage of the water from the pump to flow directly back to the pool and this may lower filtration efficiency. With minor gasket wear this has not be a problem for us even during vacuuming.

Larry

[riegal]

Thank you for the response.

Had the filter sand changed about 8 months ago, so it shouldn't low sand level or clumping. And this problem just showed up so I wouldn't think its short feeder. But not sure what a short feeder is so I'll check. Maybe then it's a collector problem. But, again, not sure what a collector is, so I'll see how to check that out.

Question, should water go to waste when backwashing? I didn't think it should but a response on another forum said water does. And if that's the case I noticed the drop in pool water level this time because my wife let the backwash run for 10 minutes whereas I only do it till the water turns clear (45 seconds - 1 minute or so.)

Thanks, this is all a learning process for me.

[riegal]

Well just did some more research & answered my own question. Backwash water does go to waste. Didn't know that. Like I said, it's a learning process.

Still I'll check out what you mentioned in you answer, seems like that may be prudent.

Thanks again.