Raising CYA with trichlor pucks question...

[Jumpin' Joan]

With the advent of cooler weather, hail storms and El Nino rains, my CYA has dropped from 50 to 40 and now to 30 (rounded up to the nearest 10ppm) over the last three months. During the last two months, daily chlorine loss ranges from 0 to 1ppm depending on windfall debris and airborne particulates (not to forget bird droppings) which are skimmed/vacuumed frequently. Gratefully, the 41F water continues to be sparkling and clear with minor CC levels if any.

Today's readings:
pH 7.5
FC 5
CC </= .5
TA 70
CH 300
CYA 26-28 (rounded up to 30)

Should I address the descending CYA with a leftover 3" - 8 oz. trichlor puck via the automatic feeder after the FC gets closer to 4 or maybe even 3ppm?

I ask because PoolMath states 7 oz. of trichlor will "raise the FC by 9.6, CYA by 5.8, and lower pH .51" which concerns me because I don't want a return of metal staining due to a sudden push of chlorine/pH levels despite maintaining an appropriate HEDP sequestrant level.

As always, thanks for your help and wishing everyone a Merry Christmas and prosperous New Year!

 

[Richard320]

Short answer: yes.

Remember, that pH drop will only occur after the whole puck has been dissolved, which might take a couple weeks in cold water. pH tends to rise over time, so it may just cancel things out.

 

[Jumpin' Joan]

Thanks Richard ~

Just a little paranoid here when it comes to risking the dreaded return of staining. The pH does creep up predictably over a 7-10 day period with small additions of bleach to maintain water balance this time of the year so it's no big deal if trichlor moves it down a bit.

Happy Ho Ho and all that good stuffing!

 

[Casey]

If you don't want the FC to go up, you can always go with stabilizer. It's just another option.

 

[peachy]

he's got leftover pucks.