Pink slime!

[waterbear]

Here's the one thing that niggles at me. I don't mind keeping FC higher than where I've kept it -- around 3.0 -- except that Jandy's SWCH says that I can cause damage to pool metals by maintaining FC higher than 3.0. I don't know if there were talking specifically about the metals as part of the SWCG, or if that's their position for general water balancing. Since all my Jandy equip is under warranty, I'm hesitant to maintain FC higher than 3.0. Thoughts on that matter?

Thanks

Thoughts on the matter is that low pH is the main factor that can damage metals in a pool. High chlorine with stabilzier is not really high chorine. If you had and UNSTABILIZED pool then 3 ppm FC would be rather on the high side.

As far as your calcium, brin it up to 400 to 450 and drop your TA to about 70 ppm.

You might noit have noticed a faster pH rise when the pH is lower but the chemistry behind it supports it. The lower the pH the more bicarbonate (TA) is converted into carbonic acid (basically CO2 in water) and the operative word here is acid. The more CO2 in the water the faster it outgasses, particularly with a bit of aeration going on, either from your waterfall or from the hydrogen bubbles in the salt cell. Therefore by minimizing the on time of the salt cell (by running the CYA at the upper limit and also running the FC at a level appropriate for that CYA level) AND by lowering the TA to reduce the amount of bicarbonate in the water that can be converted into carbonic acid AND by limiting how low one drops the pH, once again to limit the amount of bicarbonate coverted into CO2 one effectively slows down the outgassing of CO2 and the associated pH rise. Many manufacturers don't understand the actual chemistry that is occurring and they attribute (incorrectly) the pH rise to the formation of sodium hydroxide in the water. Jandy is owned by Zodiac and I do not have a very high opinion of that company.

Jandy's recommended water balance levels are just the industry "standards" that manufacturers regurgitate to the public with no real understanding of water balance and they have changes quite a bit over the years. The FC should not be over 3 ppm is actually an outdated recommendation based on lack of understanding as to what CYA actually does (even though the CYA/Chlorine relationship has been known since the 70's and even published in books and articles. Nowadays, a general rule (and still incorrect) is that FC should never go below 2 ppm and should be up to about 4 ppm but this still does not work for CYA levels that are commonly found in pools running exclusively on trichlor or in salt pools.