Cloudy water after SLAM

[molokoid]

Hi all, after some recommendations on next steps please...

After a spell of poor UK weather and me working away the pool had gone to low / no chlorine and had some slight green + visible algae on the steps. Started my SLAM and have kept to it for 9 days now. The green on the water cleared after 2-3 days. and i've maintained FC at around 10 (above what my ColorQ will read), with it dropping to 5.09 on occassions. pH has stayed around 7.3. ALY 90-98, CYA 64-80.

Pool has been 'stuck' at this cloudiness for almost a week, filter running 24/7

Any advice on my next steps (as you'll see from the photo i've started draining to waster and filling with fresh in some desperate hope it'll be good for kids to go in while we have the good weather)

Thanks in advance

[Denniswiseman]

Could be your slam hasn't finished properly
Let's have your numbers (CYA is very important)
FC:
TC:
pH:
TA:
CH:
CYA:
Is this a salt water pool or a standard chlorine pool and how do you chlorinate

[molokoid]

I'm surprised (albeit at my learner level), that 10 days of SLAM wasn't enough. I did state the range my CYA had been fluctuating between, but i'll probably get a test done in the morning and post them all in the format you've said.

I think my error has been that i've been raising FC to about 10, which may be me misreading a table of recommended levels, plus the fact my kit (ColorQ) can't measure as high as it probably needs to.

Thanks, i'll be back!

[Denniswiseman]

You didn't say how you chlorinate
A Slam (Shock Level and Maintain) with relation to Chlorine / CYA Chart and Recommended Pool Levels
Pool Maths
Overnight chlorine loss test (OCLT)
A slam of 10 should be sufficient but must be maintained
When testing with the ColorQ mix an equal amount of distilled water with the sample, test and double the result. I don't think it will work with CYA
You can safely swim up to your shock level for your CYA
Excessive CYA renders your chlorine ineffective and you have to use more to get the same sanitation
For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm.
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm
To reduce your CYA you have to do a partial drain and refill, which you are doing now
Continuous use of Trichlor/Dichlor will raise your CYA which means you have to raise your chlorine level as well