Slamming take two!!!

[trivetman]

So I pulled the tarp off a few days ago to say hello to the pool after a long winter. Like usual after the winter it was filthy and a bit green. A couple gallons of 10-12% usually clears it up and then I go through maybe 1 ppm per day until summer warms the water up. This year, those couple gallons made the water clear but the pool wouldn’t hold chlorine. So I got this….cause I lurk on this forum all the time right! Bring it up to SLAM level for a couple of days and last night I passed the overnight test and no cc, so time to let the fc drift down.

BUT…I tested tonight and the pool dropped from 11.5ppm to 4ppm fc over the course of the day.

Maybe one of my tests got screwed up and the pool actually lost a lot of fc last night? Is there anything to do but go back to SLAM level and hold it until I pass the overnight test again?

 

[trivetman]

8 pm Wednesday
FC 4
CC 0
TA 60
Ph 7.7
CH 340
CYA 30

8 am Wednesday
FC 11.5
CC 0

10 pm Tuesday
FC 11.5

 

[trivetman]

And this Thursday morning FC tests at 3.0, so again passes the overnight test.

I know that a pool will lose more chlorine from a high level than from a low one but losing 7.5 in a day when its not all that hot is a lot more than I had expected.

Do I need to SLAM again?

 

[wireform]

You're confusing me with your reported numbers.

 

[trivetman]

Whats not clear? Its a time series

I edited above posts to include day labels. Maybe that helps

 

[trivetman]

Ran the swg during the day at 50% power for 6 hours and fc stayed stable, tested at 3.5ppm at the end of the day.

Maybe I am good.

Maybe I am talking to myself

 

[wireform]

Trivet
The short answer is you're not great. The SWCG requires 60-70 CYA levels and you're running it at 30 which even in a non salt pool would need to be in target range of FC 4-6. I like running a FC always on the hot side of target for extra insurance against algae. For the SWCG CYA level of 70 the target is 5 and there I also like it +2 which is at least FC 7 to be again on the hot side of target. Bathers will never know the difference and should something go awry you'd be safe for a little longer.

 

[trivetman]

Wire - i hear you. Cya buildup will happen shortly as well as raising the fc level. I am just relieved the pool held chlorine two nights in a row and that the swg held the level today. Probably means the pool ate 1.5-2ppm over the course of a sunny but cool day which is about right.

I just got kinda freaked out a couple days ago when fc dropped from 11.5 in the morning to 4ppm that evening. Maybe I had some testing error? Hard to say.

The swg is a new install this spring. I closed with a cya level of probably 40 last fall when I was using bleach

 

[wireform]

Trivet
Now that you have a salt cell you need to enter the correct information into the pollmath app for it to spit out the correct answers. Make sure you have the salinity checked off and CSI which is key in keeping the cell healthy and happy. We can't see your poolmath logs unless you opt in the menu to share.

 

[trivetman]

Gotcha. I am very used to monitoring the csi and just saw how much the salinity affected it. I’ve never logged results in it but ill take a look at how it works

 

[wireform]

CSI for a SWCG pool needs to be slightly negative of "0"