NO FREE CHLORINE

bjpeters

Member
Jun 7, 2010
18
Split from here: no-free-chlorine-t44900.html Butterfly

I am having a very similar problem with no free chlorine at spring start-up. I have a 16,000 gallon above ground pool - initially the pool store tested my water: TC 7.5, FC 0, Total Alk 184, Total Hardness 236, CYA 30.

I have added an unbelievable amount of chlorine and still have minimal FC readings. I have added 7 gallons of Pool Shock and 10 lbs of trichloro - looks like I am maybe finally testing FC at 1 but have not gotten it any higher.

Hard to believe I need to add this much chlorine - plus more. Any suggestions for me also? I do have a Taylor test kit so at least I have that going for me......which is nice. I always wonder what is the best and most economical type of chlorine to use in these situations. The pool store wanted to sell me 24 bags of Burn Out3 or 25 lbs of Zip Chlor - think these would be expensive options, correct?

Appreciate the help.
 

Bama Rambler

Mod Squad
TFP Expert
Bronze Supporter
LifeTime Supporter
Jun 22, 2009
23,626
SouthWest Alabama
Bleach or liquid is the most economical in most cases. They're also the ones that don't add things to your pool that can get out of hand.

10 lbs of trichlor would have raised your CYA by 42. So if we believe the first numbers your CYA is now 72 and that's too high to try and shock (which is what you need to do) with. Use your test kit to give us a full set of test results and we'll go from there.
 

bjpeters

Member
Jun 7, 2010
18
Actually my CYA was at 0 before I added the trichlor - it read around 30 after adding the 10 lbs of trichlor. I did go out and buy more pool shock and based on everything I am reading here, that is all I will use to shock my pool. It appears that I have maintained my FC level overnight after shocking with pool shock and I believe my CC is now at 0. That was only after adding more pool shock. I have ordered the FAS-DPD test kit so that I can more accurately determine FC levels. The water looks great - very clear - so wondering if I have reached the endpoint of my shocking? Would the recommendation be to keep checking the FC to see if it holds - and at what level?
 

linen

TFP Expert
LifeTime Supporter
Jul 30, 2010
8,649
Twin Cities, MN
bjpeters said:
Would the recommendation be to keep checking the FC to see if it holds - and at what level?
I would, since your pool has required so much chlorine to get here. I am assuming you have read the OCLT procedure?

Assuming Bama's number for 42 ppm cya due to all of the trichlor, then your FC shock level is 15 ppm according to poolcalculator.com. Dose your pool above that level in the evening, then after and hour of circulation test for FC and CC, then without any more chlorine being added to the pool (turn of any swgs) test again before the sun hits the pool in the morning and see how much FC your lost and what your CC level is.