I understand how FC and pH change over time based on sun, usage, etc... but, assuming normal evaporation and refilling and no draining of water, how are CH and CYA affected by evaporation? Are they both not affected by evaporation and essentially stay the same over the course of a summer, unless a large amount of water is pumped out? Or do they slowly decrease over time with standard evaporation and refill with water that essentially has zero CYA and CH?
CH and CYA over time
- Thread starter jtech1
- Start date
They're not affected at all by evaporation and refilling. CYA is very very slowly oxidized by chlorine so it would slowly go down over the year.
This is because evaporation on only evaporates water since CYA and calcium are not volatile. CYA is not in fill water, but CH often is so with evaporation and refill the CH will rise from adding it via the fill water. Water dilution from splash-out, carry-out, backwashing, rain overflow, etc. will lower the CYA and CH levels.
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