Sand filter isn't cutting it.. new filter ideas?

[Bedlam]

I have a 25k in-ground pool, 1hp pump, about 30-40 feet of head, so my hayward pump is going 50-70ish gpm (from their chart anyway).

I had a HUGE problem with algae this year, and no matter how much I shock it, it's not clearing up. I've tried everything. Crazy amounts of shock and bleach. It's much better than it was, but still, only about 6 feet of visibility. Even the 3 feet of shallow end is cloudy.

No mount of classifiers has helped.

I just don't think the algae is being filtered out. I think it's mostly dead, but the water will not clear. Running the pump 24 hours doesn't do much. It's a sand filter which freshly replaced sand.

I was looking at D.E. filters, which I've owned in the past, as well as cartridge, which I've also had (a very old model from 20+ years ago). This is my 3rd in-ground in a row, 25 years of pool ownership.

I was actually leaning towards cartridge filters over D.E. and came across this:
Reliant® RSC Series 425 Sq Ft "Quad" Cartridge Filter - FREE SHIPPING!

Never heard of that brand, and couldn't find any reviews, so I was weary, but it's like $150-200 cheaper than Hayward and Pentair.

Any suggestions would be appreciated. Money is tight and I really don't want to replace the Sand filter, but I've always hated them. My first pool had the same cloudy water problem with a sand filter. I replaced the filter with a D.E. and it was crystal clear 8 hours after installation, so...

 

[BoDarville]

Welcome to TFP!

Before you go spending lots of $ on a new filter, let's consider a couple of other possibilities first.

1. Did you follow the SLAM - Shock Level And Maintain process and stick with it until all 3 of the criteria of done were met? Since one of the criteria of done is clear water and your water is still a bit cloudy, it is an indication that the SLAM or shock process you were following was aborted too soon.
2. Have you checked behind light niches and in & around pool ladders, if either applies to your pool?
3. If you have "portable" wedding cake steps in your pool, have you checked underneath them?
4. Have you tried an Overnight FC Loss Test?

Items 2 and 3 are favorite hiding spots for algae that may not appear on the pool surface. If you fail the Overnight FC Loss Test, then that is evidence that some form of organic matter is still present in your pool and consuming chlorine. It also may explain why your water is cloudy.

While DE filters will indeed filter down to a smaller micron level than sand filters, I have a sand filter that is at least 8 years old. I can clearly see the bottom and can tell that the screws holding the drain cover in place are Phillips-head.

 

[Texas Splash]

Welcome Bedlam to TFP! I encourage you to take Bo's advice above. He speaks the truth. :blah: Not only do we like to see members with clear water, but we also try to help them save a buck or two along the way. I suspect the root cause of your problems are chemical-related as well, and no amount of filtration will resolve a chemical problem. Nice to have you with us.

 

[Bedlam]

I'll look into it. I'm mostly going off past experiences here... When I used to have a sand filter (new) and it just didn't cut it after 3 days, and I got a D.E. filter that cleared the pool in 8 hours.

I added 6 gallons of bleach last night and the color of the pool changed from shades of green to blue, but definitely still cloudy. I still think the filter isn't taking out the dead algae and other small particles, but I really don't want to buy a new filter. It's just getting to a point where I'm spending a silly amount of money on bleach and chlorine.

I'll check the ladder/light areas too. Thanks.

I'll check out the SLAM link.

 

[Isaac-1]

Do you have any testing numbers? Without quality test numbers you really are just guessing what is going on, and if you have been dumping this and that into the pool trying to get it to clear up you may have driven your CYA or CH sky high. At high levels CYA can prevent chlorine from being effective, and at high levels CH can cause calcium clouding which can further confuse things in the middle of trying to clear algae.

 

[danpik]

+1^^^^ Before I found this forum my pool was doing the same thing. Could not figure it out. when I got my good test kit I found my CYA was too high, way way, too high.

 

[duraleigh]

Read this forum and you will find literally hundreds of posts complaining about their filter not keeping the pool clean when the problem is a chemistry issue and has little to do with the filter. Can you post a set of current test results?