How to test Sodium hypochlorite % in liquid Chlorine

smeestu

Well-known member
Oct 26, 2014
69
Thailand
#1
I have been reading a fair bit on here and i couldnt find it .My problem is that i have to ship liquid chlorine from 500 miles away so i would like to buy it in reasonable amounts . The room i will keep it in is well ventilated but will have a temp of anything upto 85-90 in the day time .The question i have how to test the strentgh of the stored chlorine as it drops off over time rather than just putting it in the pool and check the readings can di it under a more controlled way so i can add it to the pool ocording to strentgh .
 

Isaac-1

TFP Expert
LifeTime Supporter
May 10, 2010
6,711
SW Louisiana
#2
I know of no commonly available test kit that will measure anywhere near that range, although I am sure there are professional methods, and someone should be along soon with a better answer, on a side point have you considered getting a SWCG (Salt water chlorine generator) for your pool which would let you avoid the vast majority of liquid chlorine demands, as I suspect common salt is probably easier to obtain there?
 

smeestu

Well-known member
Oct 26, 2014
69
Thailand
#3
Thanks for your input i would like to purchase a SWCG at some point when funds permit unfortunatly they are between 25-50% more expensive here in Thailand than in the US or AUS i do have some friends scattered about maybe if they come for a visit they can put one in there suitcase :) .As for salt there are large salt "fields" within 30 miles of my house i guess that would be ok for the pool they sell it on the side of the road in huge bags i suppose it should be ok maybe dilute it first .
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#5
It is possible to measure bleach concentration using a standard test kit, but it requires care and can easily go wrong. You need to do a 10,000 to 1 dilution of the bleach, and can then measure the result with your standard FC test. The issue is that very high dilutions like that are error prone, most especially they are subject to cross contamination.

One way to do the dilution is to add 10 ml of bleach to 1 liter of water, mix throughly, then add 10 ml of that to another liter of water, mix throughly and then test the FC level. The two liters of water need to be chlorine free, commonly distilled water is used. Also, the 10 ml measurement needs to be as accurate as possible, typically done using a syringe or pipette.
 

smeestu

Well-known member
Oct 26, 2014
69
Thailand
#6
Thanks for the advice i have a syringe that does 10ml in 1 ml steps so il give it a go ,be interested to see what % it is when i got it, as it is 4 weeks old .