Two weeks ago I had a terrible issue with a high CC level on my swimming school. My main instructor and some of the students got a rash problem. The CC Level got up to 1.5 ppm. Last weekend I decided to SLAM the pool raising the FC level to 20 and hold it all the way through friday night to monday morning. I manage to low the CC level to a safest <0.5 ppm. No more complaints about skin conditions so far.
Since this is a totally Indoor Pool, with a rather low CYA level of 20, and no sunlight touches the water surface, I understand that keeping CC is a challenge. I consulted the guy at my local pool store about this issue, and he stated that, since I was using just bleach as a sanitizer, the usually high pH levels (7.7 - 7.9) in my water will produce higher levels of CC. Thus, I decided to add .5 to 1 lt of muriatic acid everyday to keep pH level between 7.2 and 7.6. TA has been consistent at 80ppm for the last three months, but I expect that to lower due to the muriatic acid action. Also the pool technician recommended the use of a non-chlorine shock product (ozone based) in a weekly basis to get rid of the chloramines in a four-hour period. This is a rather expensive course of action and I am not sure this is the best for my pool.
Also I was reading that Chloramines when given off from a pool in the form of a gas will redissolve in the pool unless removed by an efficient ventilation system. So, I decided to keep all the shades and windows open in the building to give some more fresh air inside and around the water area. I use a cover over the pool every night after regular class schedule to keep the water warmer, but now I am concerned that this will interfere with organic compounds oxidation which will aggravate the matter.
Would anyone like to elaborate on these?:
1) High pH levels will increase the chances of getting higher CC levels?
2) Getting a better ventilation in the pool area and perhaps not using a cover will help to keep CC rather low?
3) What other actions can be taken to prevent CC level scalating?
Thanks in advance
P.S. I found this information illustrating.(Controlling Chloramines in Indoor Swimming Pools)