help adjusting

[poolhelp101]

replaced my liner and filled with city water. having trouble getting the chlorine to hold. I have kept at shock for a couple of days but each morning there is no chlorine holding overnight and PH is high. i have 21,000 gallon inground, vinyl liner. water is clear

FC-0
CL-0
TA-130
PH-8
CYA=30
i do add bleach thru the skimmer.
please advise

[BigDave]

How did you add the CYA and in what form?
How much bleach have you added at a time? Have you measured FC an hour after adding bleach? FC - 0 means it never turns pink when you add the DPD powder?

[poolhelp101]

it does not turn pink after adding the DPD. i did not add any cya and unless i have tested it wrong, 30 is what it is showing. i have 3 of the 8.25% bleach at night around 9 pm est and i have not tested until morning and then I find no chlorine. with it not holding at night

[BigDave]

I would expect no CYA in a fresh fill of city water - perhaps review the test procedure.
No pink - no chlorine.
I am not at all surprized that a pool with no CYA loses all it's FC in a day. If you haven't added any CYA then you haven't any.
If this were my new water, I'd start chlorinating with dichlor (99% Sodium Dichloro-s- Triazinetrione Dihydrate - 1% inert ingredients - 55-56 % available chlorine accept no substitutes and nothing with copper). Dichlor adds FC and CYA and drives pH down - all adjustments this pool needs. It is also a quick way to get CYA into the water. Every pound of dichlor should raise this pool's FC by about 3.2 abd CYA by about 2.9. I'd chlorinate with dichlor as needed (testing FC, CC, and pH 2-3 times daily until FC holds all day) to keep the FC above 3 until I'd used 11 pounds of dichlor. I'd then measure CYA and continue dichlor chlorination until reaching the CYA target - then switch to bleach for chlorination.

[poolhelp101]

okay i will do this. what should i get my cya target to?

[Watermom]

For most pools, 40-50 is about right.