Lithium hypochlorite and FC

Dasdubtech

Member
Jul 13, 2016
15
Dallas,GA
I was over at a friends house last night. She is working on some small issues with her pool. Mainly high CYA (tick over 100 using the tf100 kit) so subject came up as her FC was .5. She had bought Burnout 35 to add. I don't think they are sold yet on bleach. So she added the burnout and I waited about three hours to recheck FC. FC got a bump to 1.5 and CC bumped to 3.0. CC was .5 to start with. I do not use anything but liquid chlorine in my pool. Never have had CC issues. Im trying to understand why we had no real rise adding two bags of lithium hypochlorite??? Like is said I don't and will not use any of this stuff. Seems there should have been a much better change in FC! Any input?
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,347
NW Ohio
You don't say her pool size, but two bags of lithium-hypo would raise 10k gallons of water 8.5 ppm FC. It isn't very strong stuff for the price and that's why we don't suggest it even though it is fine to use. The CC's do not have anything to do with the type of chlorine used, there is something in the water reacting with chlorine is all. With that high CYA 0.5 ppm FC may as well be zero, so adding more brought the FC high enough to react with whatever is in the water. With that high CYA level the FC target to SLAM a pool would be more like 40-50 ppm so 2 bags of lithium-hypo isn't going to do much at all.
 

Dasdubtech

Member
Jul 13, 2016
15
Dallas,GA
I convinced her to go buy liquid today. Pool is a 13,500 ag. I just figured according to pool math we should have seen FC go up to at least 7. Moral to the story is that she needs to quit using all the pool store stuff and get some real FC in the pool. I had no experience with lithium hypochlorite. Seems to me like it produced no real FC. We retested after 4 hours. I guess my question is does this stuff take much longer than that to show up on FC test??? She doesn't want to spend the time draining and refilling to correct the cya. I gave her the chart. It's gonna take a lot of chlorine for sure no mater what.
 

Donldson

TFP Expert
LifeTime Supporter
In The Industry
Jun 12, 2009
3,347
NW Ohio
It produced plenty of real FC, which then reacted with whatever was in the water. There is no magically slow registering FC or anything like that, just a pool with a chlorine demand that is not being fulfilled. 7 ppm FC introduced by lithium-hypo is no different than 7 ppm FC introduced by any other method. If you had introduced it via liquid chlorine you would have seen the exact same results. There is nothing special about lithium-hypo once it is in the water.

I hope you told her that it will take about 7 gallons of 10% chlorine just to get the FC up high enough to do anything good, plus plenty more to maintain it since she won't do anything about her CYA level. Better adjust the pH first, you won't be able to get an accurate reading with the FC that high. And if you are testing the FC for her you will want to get some refills on your FAS-DPD supplies, testing that high a chlorine level will burn through those quickly.
 

Dasdubtech

Member
Jul 13, 2016
15
Dallas,GA
She's dumping!! She's getting a reading. Not worth talking about yet. Luckily the pool is not green. Just a little cloudy. Thanks for your input. Everything was in pretty good shape aside from cya and FC. She know's now. No more dychlor or trychlor. Just going to take some time to get FC up. She is going to keep chipping away at the cya. We get a great deal on liquid 10% bleach in our area. I've been down that road when I first got my pool. High CYA is a real pain!
 
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