Why.

[TwoBananas]

pH 7.3
Cl 5+
FC 9.5
CC 0.5
CYA 20
TA 160
CH 350

I slammed my pool starting about two months ago. It went from literal swamp to this lovely array of swimmable numbers.

But it remains cloudy blue. Five feet of visibility.

Pressure is low if the filter appears crystal clean.

Chlorine loss is minimal. Losing about a point a day.

Vacuum runs all day, filter runs 24/7, filter emptied multiple times a day.

It’s been about three weeks.

Why is this pool still blue?

 

[Texas Splash]

Can you post some pics of the pool? A couple different angles?

 

[TwoBananas]

Can you post some pics of the pool? A couple different angles?

 

[Texas Splash]

Those pics confirm algae. You mentioned a SLAM two months ago, but if you didn't "maintain" it and pass all 3 criteria, the SLAM Process was not technically completed. I would recommend increasing your CYA to a solid 30 and maintaining an FC of 12. It's important to do everything on the SLAM Process page for best success. Don't forget to inspect behind a light (niche) and inspect under any drain covers.

 

[Mdragger88]

U didn’t finish. Your current fc level is just barely keeping algae at bay.
Go back to the SLAM Process w/ 30ppm of cya as Tex recommended
FC/CYA Levels

You are done when:

CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
the water is clear.
(Crystal Clear w/no algae dead or alive)

*Check & scrub every nook & cranny where algae may hide (light niches, drain covers, ladder handrails, skimmer throats/weirs, etc.)
*Run slam level water through all water features & lines for at least a couple hours a day during the SLAM Process.
*Brush & or vac daily (this breaks up biofilms that algae uses to protect itself from chlorine)
*Backwash/clean filter when pressure rises 25%over clean pressure.

It is safe to swim with fc levels anywhere between minimum & slam level for your cya so long as u can see the bottom of the pool for safety purposes.