If it's not one thing with a pool it's another

stev32k

0
LifeTime Supporter
Mar 29, 2009
492
Mobile, Alabama
There was a post a few days ago about using DE in a sand filter. I have tried that in the past, but the pool was so cloudy I had to backwash about twice a day and it didn't seem to do much good because the flow would drop to almost nothing before backwashing so I quit. After reading the thread and seeing where people claimed a big improvement I thought I would try again. My pool water has been clear as glass for months, but I thought maybe the DE would improve the appearance even more.

The day before yesterday I added 2-1/2 cups of DE to get a 1 lb pressure increase across the filter. I turned off the pump timer and let it run around the clock. Yesterday the water was clear, but I could not tell any real difference. The filter pressure had not increased at all - so-far-so good. The pump ran all day and all night and today the pool still looked about the same as always and the filter pressure was still where it was when I started.

This afternoon I decided to skim some leaves off the surface and was walking around the pool and came to the shallow end directly across from one of the returns and when I looked down the bottom was a nice pure white - WHAT IS THAT? My first thought was the liner had been bleached out, but I got out the pool brush and brushed the bottom and a nice pure white cloud came up. OH Crud - it looks like some of the DE got though the filter and settled out on the bottom. I started brushing in a few more places and everywhere I brushed a white cloud appeared - no wonder the pressure had not increased all the DE went though the filter into the pool.

I'm reasoning the only way that could happen is if some of the inlet water is short circuiting the filter and going straight to the outlet. That must mean the multi-port valve gasket is bad and I just happen to have a spare. I've learned that the gasket should be replaced and the spring and stem assembly lubed up about once a year. So I remove the top of the valve and start to scrape the old gasket out, but think to myself I better wait and make sure I can find the spare first. Well I find the spare, but guess what - it's the wrong gasket and will not fit my valve. So I'll have to make another trip to the pool store tomorrow and listen to everything I'm doing wrong in caring for the pool from a 19 year old high school drop out. I hate going in that place. I don't want to be rude, but it's all I can do to keep my mouth shut.

Now I'm going to have a heck of a time getting all the DE out. Guess all I can do is vacuum the entire pool and hope it stays in the filter this time.
 
Re: If it's not one thhing with a pool it's another

While you are removing the MPV, note to yourself how much friction exists as you lift off the MPV. If it isn't tight, it's possible DE shot in the return pipe. A slight crack in the pipe is another possible cause. It might be visible if, after pulling the MPV, use a shop vac in wet mode to draw the water out of the tank from the up pipe. Happens sometimes with Haywards.

Scott
 
Pool Clown said:
Also, does your internal air bleed (tank bleed) still have it's screen?

I don't believe this filter has an air bleed. It's a hayward model 244T, but it's an older model (1991) and does not even have a bottom drain.

P.S. I didn't pull the valve body just the top, but guess I should. I haven't looked at the sand bed in two or three years. I'll also inspect the inlet pipe for damage.
 
I found the problem it was not the gasket it was the O-rings on the valve stem. They were hard and grit bound them up so that the valve was not closing down all the way. The inlet pipe looked good and there was no evidence of channeling. However, the top of the sand was almost completely covered with dead ants. There were hundreds if not thousands of them. Guess they are not being back washed out. I removed the ants, added 50 lbs of sand, buttoned every thing up, and it is now in service - and hopefully working like it should.
 
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