Another Free Chlorine Question

[svtsml]

Hello,

I found this forum recently looking for answers with my pool. I learned alot from everyones advice and all the help topics and charts. I read all the pool school topics, most of the posts and still puzzled. My free chlorine level is at 0.5 ppm and I can't seem to increase the value.

I raised my CYA to 67 ppm which was pretty low before. I thought this was my issue but found this didn't work. I checked my shock treatment on the pool calculator which told me I should shock at 15 ppm. I plugged that number in the goal value in the fc section and the calculator told me 8lbs of calhypo 65. I put 8lb in the pool and retested it again an hour later with no reading. Put 8 more pounds with noreading. I am at a lose with this. I am problably doing this all wrong so seeking anyones advice.

My pool is a 35,000 gallons DE filter using pucks in skimmer
My test are
fc 0.1
tc 0.4
cc 0.24
ph 7.4
hardness 191 I need to raise
ta 74 need to raise
cya 67


I also asked my local pool store about my results he said I shouldn't use Calhypo because in could raise my hardness too high? He recommened sodium based super shock.

 

[jblizzle]

Welcome

Obviously something is consuming all your FC. I too would recommend avoiding the cal-hypo for the same reason. I would also avoid the tablets as your CYA is already above what we would recommend (30-50ppm for a non-SWG pool).

You best bet and cheapest option is liquid chlorine/bleach to shock. It may take a LOT of bottles before you can start to hold a FC level ... but you have to follow the Shocking Your Pool process.

And to do that process correctly, you need your own good test kit with a FAS-DPD chlorine test (see my signature for recommended kits)

EDIT: BTW do not worry about TA and CH levels ... they are fine for now. Focus on FC!!!

 

[svtsml]

Jason,

Thank you for your reply and suggestion. 10 gallons of bleach is alot! How soon can someone swim after treatment? I know the recommentation is bleach but what effects would diclhlor supershock do? it only requires 9lbs.

Thank you again for your help!

 

[jblizzle]

Read Recommended Pool Chemicals

Di-chlor (and tri-chlor pucks) add stabilizer (CYA) and like I said, you are already on the high side. 9 lbs would raise your FC by 17 and your CYA by 16 ... not good!!!

You can swim up to the FC shock level for your CYA. But, since you need to shock your pool as something is consuming your FC, you need to keep your FC ABOVE your shock level ... this is not a 1 time addition of bleach. You will need to be adding bleach every hour or so to start. Read Shocking Your Pool again or for more details Turning Your Green Swamp Back into a Sparkling Oasis

It is not unheard of for people to use well over 30-50 bottles of bleach in the process of shocking a pool ... and since your FC appears to drop quickly, you may need a lot.

 

[svtsml]

Thank you! Out to Walmart for some bleach!

 

[jblizzle]

Not much hurry on getting a bunch of bleach until you are capable of testing for the high required FC levels.

Posted with Tapatalk ... sorry if I sound short ... hate typing on phone