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View Full Version : CYA, trichlor and chlorine effectiveness question



JohnInSoCal
06-14-2006, 08:23 PM
I am farily new to owning my own pool (1 year) and have been reading up on pool chemistry on this site and others on the internet and I find this stuff all very interesting.

So my BIG question is even at higher/very high levels of CYA is chlorine still effective at fighting algae ? I ask because although I am new to having my own pool, my dad has had one for years, grandma etc. And they always used the floaters with trichlor pucks and never had an algae problem in many many years of NEVER draining the water to lower CYA. I'm sure they have no idea what CYA/stabalizer is and it was probably very high since it was only removed by splash out/carry out/very occasional backwash. All they would ever test is chlorine, if it's yellow on the test they figured everything was great.

I like to use trichlor in an erosion feeder because it keeps a constant level of chlorine in the pool. The drawback is higher CYA. I was on a strictly bleach/chlorine routine but got lax and had an algae problem (all fixed up now) but I would like to avoid that in the future.

thanks,
-- john

CarlD
06-14-2006, 09:43 PM
I suggest you go to PoolSolutions.com and read about running a high CYA pool. (rather than typing it out). Really, all you need to do is:
1) have a FAS-DPD test kit so you can measure higher chlorine levels.
2) Determine the normal and shock levels for your CYA level. For example, if your CYA is 100ppm, your FC normally should be in the 8-15ppm range, never lower than 8ppm. Shock by raising FC to 25ppm. Despite those high levels, you shouldn't have to add much chlorine to maintain them, and you should still have a nice, sanitary pool. You MAY want to wear older bathing suits as they may fade a little.

JohnInSoCal
06-14-2006, 10:48 PM
thanks. I have the fas-dpd kit and will continue to monitor CYA, currently it's between 40-50. I guess I will just have to see how much it rises over time and adjust my chlorine level to fit within the reccomended range with the CYA (I have seen the chart). It's not a huge deal to drain some of the pool off and refill if the CYA gets out of hand (water is very cheap here). I am curious to see how much it will rise over time when I am on the trichlor erosion feeder.

My wife thinks I'm being way too anal about all this chemistry and testing stuff. She says "my mom never tested a darn thing and always had crystal clear water with no algae" lol.

thanks,
-- john