[Dichlor/bleach Method In A Nutshell]

Though the addition of a hypochlorite source of chlorine such as chlorinating liquid, bleach, Cal-Hypo or lithium hypochlorite has the pH rise, the consumption/usage of chlorine is an acidic process so the pH drops back down when this occurs (technical details in this post). Any net pH rise comes from two sources: 1) outgassing of carbon dioxide, which occurs faster at higher TA and lower pH (see this table) and higher aeration or 2) from the small amount of "excess lye" in bleach and chlorinating liquid. Clorox Regular unscented 6% bleach has the least amount of excess lye in it. Off-brand Ultra bleaches often have more so would tend to have the pH rise more quickly. Maintaining a lower TA (down to 50 ppm, if needed) and using 50 ppm Borates helps reduce the rate of pH rise.

I use only 12.5% chlorinating liquid in my pool, yet the pH is stable only needing a small amount of acid added every month or so.

Let's say I want to drain, clean, and refill and go straight to bleach, bypassing the dichlor step. Can I just go out and buy some CYA and immediately bring the CYA level up to 30 ppm on the same day I clean, refill, and balance the pH?

[Nitro's Approach To Water Maintaince]

As for the spa after Borates are added, certainly the Borates will help stabilize the pH, but it won't change the amount of acid that would need to be added if you had an ozonator. It just slows down the pH rise, but it also takes more acid to move the pH down when it does rise. So I'm sure it would still be annoying since I think one of the objections wasn't just the frequency of acid addition, but having to add it at all and in quantity. The only known solution to lowering the cumulative acid quantity is to have a lower TA (and less aeration or a higher pH target with lower CH to prevent scaling).

Someone posted that aeration only occurs when the waterfall/jets/bubblers are running AND the tub cover is removed. If this is truly the case, then why does the ozonator generally cause the pH to rise 24/7?

Or did I misunderstand the relationship between raising pH with air and the placement of the hot tub cover?

[Nitro's Approach To Water Maintaince]

The warnings about bleach are not only about using it exclusively with no CYA in the water which would make it too strong, but also that using any hypochlorite source of chlorine (bleach, chlorinating liquid, Cal-Hypo, lithium hypochlorite) will tend to make the pH rise due to aeration and high pH can lead to scaling. So you need to manage this by having a lower TA level. For some spas, such as those with ozonators that aerate a lot, there may not be a good solution as the pH rise may be too much unless one is willing to frequently add acid.

Can a weekly MPS shock help reign in the ph rise from the bleach?

[Nitro's Approach To Water Maintaince]

Hello spa gurus. New guy, first post, just drained my brand new 2-month old dichlor-dosed Jacuzzi due to a sky-high stabilizer reading. (300+ ppm)

I'm going to switch to the dichlor/bleach method if someone can just reassure me about the bleach business. Why are

there so many dire warnings out there about not using bleach in hot tubs? I already get the part about pure bleach with no CYA buffer being a problem. Is that really the main reason the warnings are out there?

OK, for the new fill (well water)....I've raised the CH to 250 , the TA is starting about 100, and the pH is well below 7. Already hit the tub with 1 TBS dichlor. If I add ph up, the TA will go up too right? So will aeration alone fix my low ph?

Oh yeah, what's Purox?

Thanks and I sure am glad to find some smart people here. The guys in the pool supply stores are giving me migraines. Bless their hearts.