Sand filter not working well

[Abxflyr]

I've read several other threads regarding sand filters, replacing sand, etc. I have replaced the sand 2 yrs ago, but for some reason this year the filter does not seems to be clearing the water much at all. I have used a garden hose with spray nozzle to clean the sand by simply moving the nozzle around inside of the filter (top to bottom); then backwashing it out. It seems like the filter is just not picking up fine matter. This is now the 3rd time this season so far where the water has become what I call 'dirt cloudy'. I treat the water with a Fall Out type product. After the treatment, a ton of matter is on the pool floor that I vacuum to waste.

So, my question is ....is there anything I can do (or not do) to retain the crystal clear water I have after the Fall Out treatment? I know about using DE powder with sand...although I also hear on some fronts its not recommended as the sand will definately clump together. HELP Please!!

 

[UnderWaterVanya]

Can you post water test info?

 

[Abxflyr]

PH 7.4
FC 8.5
CC 0.0
TA 70
CYA 41

Its vinyl, so I don't worry about Calicum/hardness too much. I do not believe there is any kind of algae problem as the salt system does a good job of keeping the CL at a good level. If I'm away from the pool for several days, I'll even drop in a 'tab' to the skimmer to assist with a little extra 'everything' (cya) as needed while I'm gone.

 

[Richard320]

pool-school/add_de_to_a_sand_filter might be an idea. Also check the circulation pattern, maybe an eyeball got moved somehow so things aren't getting stirred up where the skimmer can grab 'em.

 

[kplaster]

I didn't have enough sand in mine..Add'd 50 lbs & problem was solved

 

[stev32k]

I didn't have enough sand in mine..Add'd 50 lbs & problem was solved

Same thing here. Sand gets washed out on backwash and I usually have to replace about 50 lb every year.

 

[Abxflyr]

I will check the sand level...but with it being replaced not too long ago, I'm hoping that I haven't lost that much. It would have to be thru backwash or something along those lines as I haven't seen any sand come into the pool (that would be bad). The eyeballs are all in good shape, everything is as it's always been for circulation, etc.. I have used DE powder in that past at times, not often at all since I replaced the sand though. DE does have a tendancy to clump together the sand and the only way I know to clear that is a hand wash (via hose/nozzle). So, I didn't want to potentially ruin the new sand by using DE as much as I did in the past.

I'll let ya know about the sand level. I may need to call the manafacture and see what the depth is supposed to be to determine the right level...else how do you know when it's too little (or too much)??

 

[linen]

Post your CH value. Too little is not a problem for vinyl, but too much still can be.

else how do you know when it's too little (or too much)??

That is a problem, some manus do not state a height, just a weight. If you have a round tank, having the level near/slightly above the middle is about right, but if yours has a cylindrical portion in the center, then it is harder to say, but it is common to be about 2/3 up the cylinder.

 

[stev32k]

I have the Hayward 244T and the factory recommends the sand level to be 6" below the bottom of the top flange. A neighbor has a Hayward S310T that is larger than mine and the sand level in it is also supposed to be 6" from the bottom of the flange. His holds 500 lb, mine holds 300 lb.