adjust cya before or after shocking

[Kateyru]

I have 3 1/4 lbs. of dichlor. Filter pressure remains steady. Do I need to leave pump on 24/7 till tomorrow am?

[BigDave]

Is filter pressure steady at the same pressure as clean or higher than clean but not high enough to backwash yet?
Let's leave the pump on.

[Kateyru]

pressure is same as clean

[BigDave]

Great! Looking forward to hearing that tomorrow morning's FC level is the same as tonight's.

[Kateyru]

fingers crossed...will email you in the am!

Morning! 7 am test results are FC = 7 and CC = 0. Pump is on but SWG is off. Let me know next steps.
Thanks!!
================
Just realized that I didn't give you results from late yesterday afternoon. They were FC = 8 and CC was <.5 but not quite 0.

[BigDave]

Sorry I didn't check in sooner, been busy - beautiful day.
So ... you're right on the edge. 1 ppm FC lost overnight and .5 ppm CC yesterday.
I'd backwash even if the pressure hasn't risen to get rid of the stuff that's been filtered out. I'd also do the evening and morning FC check again tonight - just to be sure.
Next, you need to decide how to raise your CYA. I presume you want to get it to 70-80 for your SWCG.
If you're willing, you can manually chlorinate with dichlor for a while - each pound of dichlor should raise your FC by 3 ppm and your CYA by 2.7 ppm and drop your pH by 0.11.
Or you can use CYA, each pound should raise your CYA by 5.4 and lower pH by 0.1 and turn your SWCG back on.
Let us know how you want to proceed and we'll be here to help.
What's your pH? you'll need to keep an eye on it as you raise the CYA.

[aylad]

I'd backwash even if the pressure hasn't risen to get rid of the stuff that's been filtered out.

Keep in mind that a dirty filter will filter better than a clean one--if the pool has been clear since the last backwash, there's really no reason to waste the water if your pressure isn't up...

Janet