Well-known member
Aug 1, 2010
I'm just wondering what anyones thoughts were on UV for chloromine reduction. I was originally going to fit UV and a chlorine tab feeder until I found this site and realised my CYA would hit maximum too quickly. So I am now thinking of using SWG and am thinking that maybe the UV won't be needed because the chloromines won't be produced. I'm still new here and I have noticed how little anyone speaks about chloromines. I was led that these were an inevitable result of using chlorine and that shocking broke these DPB's back into chlorine? Yet a lot of people here say that if you mantain proper FC all the time ( ie with a SWG or careful testing and dosing) you should never need to shock. These two statements do not sit well together. :roll:
Another semi-relatedpoint, when you run with higher CYA and therefore a higher FC level, is your CL consumption higher or is it just that you maintain a higher level and usage remains the same? :?:

Melt In The Sun

TFP Expert
LifeTime Supporter
Oct 29, 2009
Tucson, AZ
UV does help break down chloramines, so it can be useful in an INDOOR pool where there's no sunlight exposure. Outdoors, you get plenty of UV for free already, so it's a waste of money!

Typically, higher CYA means you lose less total FC to sunlight, i.e. your FC demand is slightly lower.


LifeTime Supporter
Nov 18, 2009
Sacramento, CA
We talk about chloromines all the time...we refer to them as CC. High CC (>0.5) is one of the indicators that shocking is needed. Shocking does break down CC's, but so does sunlight. So a well maintained outdoor pool, where FC is always maintained above minimum for the CYA level, shocking is not needed because the small amount of CC created is burned off by the sun.

(MITS beat me...)


LifeTime Supporter
Jun 17, 2010
Glendale, CA
there are some detailed discussions on the chemical breakdown of chlorine but the highlights are

FC interacts with Organic material to become CC's
CC interacts with FC and/or sunlight and becomes some form of Salt
It doesn't turn back into chlorine

You may be thinking of the Bromine/Chlorine interaction
Bromine --> Bromide
Bromide + Chlorine --> Bromine

Once your pool is clean and balanced - if you maintain the proper FC level then you may never need to shock. With no large accumulation of organics or CC you never outstrip you FC for any length of time - so algae, etc doesn't get a chance to grow.


LifeTime Supporter
May 21, 2010
Southern Indiana
There is a system that uses a combination of ozonator plus a salt water chlorine generator - the ozone oxidizes organic matter as water passes through the system and also chloramines are destroyed - the result is much lower FC concentrations required - we had one for 3 years - when it worked - it worked well - quality control and material defects rendered it a hassle - so, we gave up on it and went with conventional chlorine - BBB all the way. But, I still like the ozone/SWCG idea.


Well-known member
Aug 1, 2010
I've not been anti-chlorine at any point per se, I just love anything that reduces my intervention without costing the earth. I lost a bit of enthusiasm for SWG after a couple of units I fitted for other people had problems but this was mainly due to myself as a pool builder not taking long enough to get to understand them (turned out to be faulty pH sensors and pumps usually).
Almost certain I'll be going SWG next year, I've just fitted my pH doser.
Blue or cherry? I must admit I'm at a loss to answer. :mrgreen: