Sand getting in pool - Not broken laterals or bad sand.

[Joeten30]

Hey all! I'm new to this forum and I need some help.
My wife and I purchased a home back in December that had (and still does) a 20,000 gallon in ground pool. I had to put in a new Hayward 1 HP pump in because the old one was shot. Anyway, let me get to the point. We keep getting sand on the bottom of our pool!
When I first noticed this issue, I vacuumed the sand up on the FILTER setting on my sand filter. After about 10 mins, I noticed all the nasty debris shooting right back out from the return jets. I then read online that I should vacuum this sand/dirt on the waste setting. That's exactly what I did. Vacuumed the sand on the waste setting. I even did a nice long backwash and rinse to make sure nothing would get back into the pool. The pool was looking sparking clean the next morning. My wife even went for a swim! However, later in the day we noticed the sand was coming back and settling on the bottom of the floor again!

So, I went online and I was reading about broken laterals and old sand and all that. Since I had no idea how old the sand or laterals were in my filter, I decided to change them out yesterday. Brand new sand - 250 lbs. I got that amount from my filter manual so I'm 100% sure that I put the right amount of sand in. I also put in a brand new lateral assembly. I taped the stand pipe, and cushioned the filter halfway full of water before adding the sand. There's no way I broke anything while doing this. I followed a step by step instructional video online and completed the entire process without any issues. Anyway, I backwashed right after putting the filter back together. Gave it a rinse after that. Then, I vacuumed the sand out of my pool to waste AGAIN. Once I was done vacuuming, I turned the pump off and put the filter into the filter setting. Jets running great, PSI at 10. Everything looked good.

A few hours later, I noticed the sand appearing on the floor of my pool again. Seems like the sand was in the same spots as before I vacuumed. Most of it as on the ridge where the shallow end starts to dip off into the deep end. I figured there may be some settled sand from vacuuming too fast (I was afraid to lose too much water), but there was WAY more sand than I thought would have settled.

I have absolutely NO idea what's causing this. Does anyone have any idea?

Thanks,

Joe =)

 

[zea3]

Hi, welcome to TFP! There is always the possibility that what you are seeing is not sand but accumulations of dead algae. Could you post a picture of it and a complete set of test results? That will help us troubleshoot the problem.

 

[Joeten30]

I'm at work right now so I can't post test results until later, but I will post a picture. Check it out.

 

[Joeten30]

I was doing some reading and someone said it may be the spider gasket on my multi-port valve. My sand filters does make some noise when it runs. Almost sounds like air is trying to escape or something is rattling inside the valve. Could this cause all that sand to get in the pool??

 

[CJadamec]

That looks a lot like dead algae. If you put it between you fingers and smoosh it around does it feel really gritty like sand or soft and slimy. If it's soft and slimy it's not sand.

 

[domct203]

That looks a lot like dead algae. If you put it between you fingers and smoosh it around does it feel really gritty like sand or soft and slimy. If it's soft and slimy it's not sand.

+1

That does not look like filter sand to me, and does indeed look like dead algae.

 

[duraleigh]

+2 on the dead algae. Pinch it between your thumb and forefinger....gritty? If not, it's not sand.