Question about balancing water

[wal81]

We opened the pool 5 days ago. Water was dark green. Followed SLAM process for a few days and kept pump running 24 hrs. Water is now pretty clear with some pollen settled around the bottom (not crystal clear, but can easily see bottom of deep end). Turned on SWG yesterday and set to "super chlorinate" for about a day, then switched to 50% today. My plan was to switch to timer mode after today and only run for 8 or 9 hours per day.

However, I tested FC tonight after sundown using the FAS/DPD drop test. FC was only 1. CC was .5. I know my stabilizer is low...I am going to buy some tomorrow and add asap.

So, my question....is the low CYA the reason the FC is disappearing? Or, if organic material in the water is causing it, would that mean I need to SLAM again? Last year all season I could operate the SWG less than 50% (running pump 8-10 hours/day) and never had a problem.

Also, what exactly does CC of .5 indicate?

FC 1
CC .5
pH 7.5
CYA ~10
Calc ~30
TA 95
Water temp ~63
Pool gets full sun from about 9 am - 3pm.

 

[northrn]

wal, if your water really isn't as clear as Waterford crystal, I would think maybe the SLAM isn't quite done. But a good way to check that would be to perform an OCLT. turn the SWG off. Raise your chlorine to SLAM level. Test again at dark and just before daylight. If you have a loss > 1 ppm then you need to continue the SLAM.

You're gonna lose chlorine to the sun and to organics. this way you can find out which way it's going.

 

[Richard320]

The majority of what you're losing is probably the low CYA. The remainder is organics. Don't neglect to check ladders and lights for hidden algae.

The .5 CC just means there are still organics somewhere in the water reacting with the FC.

Take the CYA up to 30 and just assume it's all there even though it won't have all dissolved and get FC up to 12. Then using bleach and the SWG, keep FC at 12.

 

[wal81]

Thank you! Do you suggest relying on bleach to get to 12 or using the SWG at 100? Is it ok to leave the SWG on while adding bleach? Keep FC at 12 until it passes the OCLT?

Also, should I keep the pump running continuously, or can I turn it off at night once it passes the OCLT?

 

[MarianParoo]

Use bleach. Some people do leave their SWG's on during a slam, but usually only if they can't baby-sit the pool. Try never to run the SWG at 100%. It will shorten the life of your cell. When it comes time for the OCLT, make sure the SWG is off. After a successful OCLT, no need to run the pump 24/7.