Fresh fill with city water - start with bleach or dichlor?

[Mm_putnam]

We drained the pool for a major refurb (new plumbing, new deck, and epoxy paint on the concrete). Filling right now with city water. Assuming it will have no CYA should I start with bleach or go ahead with dichlor to get the CYA started?

[BigDave]

I would use bleach while it's filling and switch to dichlor when it's full enough to start the pump. Wouldn't want undissolved / dissolving dichlor sitting on your fresh epoxy. Keep a close eye on pH while using the dichlor. It's probably a good idea to get pH, TA and CH tests of the fill water.

Are you filling from the hose? Did you check the water meter when you started filling - that would be a great way to know the pool's volume.

[Mm_putnam]

Does 0 for chlorine sound right? I've always thought of city water having some amount but perhaps it's too little to register with my test. I just tested water coming out of pipe and dropped two dippers of 0870 and got no color. Heading to buy bleach shortly.

On the meter - great idea. Too bad I didn't think of it in time. Good thing is we haven't used that tap (irrigation) for anything else in months so I will be able to see from my bill the gallons. We are installing irrigation right now as well so I'll check before we turn that on.

[BigDave]

City water is sanitized with low levels of chlorine or chloramine - probably wouldn't show up in a pool test. It would be more helpful to know pH, TA and CH of the fill water

[Mm_putnam]

Got the numbers just now...
FC - let's assume 0
pH - 8+. It's definitely at the top of the color chart and could be beyond a bit
TA - 20
CH - 10

[BigDave]

That's great, dichlor will help bring the pH down while chlorinating and adding CYA. Baking Soda will raise TA with little other effect. You'll need calcium as well, calcium chloride will do the trick.

[Mm_putnam]

Have been adding bleach since Friday. Added Friday afternoon and measured 0 again Sat late afternoon. Added more bleach (360 ozs.) and a couple hours later it measured well (FC at 5). Checked again this evening (Sunday) and back to 0. I just now added dichlor (bought it today).
Question - does this sound right? I'm hoping my daily loss of all FC is largely due to no CYA which the dichlor will help. And it's been sunny so that's contributing. Just want to ask if there's anything else I need to adjust. See full numbers above.

[BigDave]

Yep, dichlor will add CYA and you are losing all the FC to sun. Try not to let the get all the way to 0, test and dose throughout the day. Keep an eye on the pH now that you have the dichlor.