Algae and clarity trouble despite high FC

[wormbreeder]

We replaced our liner this spring and I got the parameters of the pool set up pretty well after a city water fill. Recently, algae has reared its ugly head and I found that I was not running the salt cell enough to keep the chlorine up. I threw in stabilized shock to get the chlorine back up fast and started running the pump more. It was somewhat good for a week or so, but now I'm getting algae again and the water is cloudy. I tried dry clarifier in the skimmer, which has worked in the past but no luck. After carefully adjusting the CYA after the fill, I'm sad to see it's up to 90 after adding the stabilized shock. I've always had an issue with high CYA.

Here are today's readings (all done with Taylor test kits):

FC: 10.2 ppm. This is more than a week after adding the shock, so this level is being maintained by the Circupool RJ45 plus salt cell.

Combined chlorine: 0.4 ppm or less

CYA: 90

Alkalinity: 70 ppm

pH: 7.2

Salt: 3500 ppm

It got dark before I could check calcium, but that was in the normal range last time I checked and I've not added any.

Suggestions?

 

[mguzzy]

The numbers look fine.. Do you get summer rains? you can dilute the CYA down easily if you do. Next time use Pool Math so you get an idea of how much CYA you are putting in. I would do a SLAM Process and follow the FC/CYA Levels. Don't mess around with Clarifiers. they can gum up your filter. When was the last time you deep cleaned your sand filter? It could be a combination of a gummed up sand, causing low filtration. And the hazy water sounds like a typical start to an algae bloom. And just use Liquid chlorine when slamming, not the stabilized shock.

 

[ajw22]

Do a Overnight Chlorine Loss Test with your SWG off.

 

[wormbreeder]

The numbers look fine.. Do you get summer rains? you can dilute the CYA down easily if you do. Next time use Pool Math so you get an idea of how much CYA you are putting in. I would do a SLAM Process and follow the FC/CYA Levels. Don't mess around with Clarifiers. they can gum up your filter. When was the last time you deep cleaned your sand filter? It could be a combination of a gummed up sand, causing low filtration. And the hazy water sounds like a typical start to an algae bloom. And just use Liquid chlorine when slamming, not the stabilized shock.

I get summer rains but also three months of 90 degree heat and sun when it's not raining. I am able to blow out some water but not a significant amount. I did the pool math and actually had the stabilizer right where it should be before I had to throw in all the stabilized shock. Should have used bleach instead. Even with CYA at 90 I don't understand how it's not clearing with consistent 10 ppm free chlorine. I'll do the overnight loss test but it might have to wait until the weekend.

What is a deep clean? I emptied out the filter and replaced all the sand with new in 2019.

 

[mguzzy]

Sand doesn't go bad.. I mean its sand!.. here is the procedure for doing a deep clean from the wiki

Sand Filter Use and Care - Further Reading

www.troublefreepool.com