New spa owner, ph drifting down - is this bad? How can I fix it?

[joecooler]

OK, so I finally popped for the TF-100. Boy am I glad I did. Now I am getting consistent readings (with one exception on hardness; no idea what that was about) and can start to dial in good spa chemistry. Per the title, ever since I got the tub (just before Thanksgiving, still on the first fill of water), the pH consistently drifts down over time. Every couple of weeks I am adding a couple of tablespoons of increaser to get it back to 7.2. Here are the other readings:

Hardness: 150 (I've done three tests over the last week, two came up 150, one came up 200)
Alkalinity: 110/120 (seems to be drifting down, first two readings were 130.

I also have ongoing issues keeping the FC level up - w/in a day of adding a tablespoon of granules it's back to 0/0.5. CC has consistently measured at 2. I know, I bought ahh-some and will be cleaning the tub w/it when I dump the water in a month or so. Don't have a free weekend do it before then.

It sounds like most folks have the opposite issue w/pH - that it drifts up. Should I be concerned that I'm going in the opposite direction? If so, what is this telling me and how do I fix it?

Thanks in advance for any help - this forum is awesome! (not ahh-some :-D)

 

[mknauss]

What are you using to chlorinate with?

 

[joecooler]

Spapure chlorine granules, 62% available chlorine. Does chlorine affect pH?

 

[mknauss]

No - but what comes along with solid chlorine can. I would assume those are Calcium Hypochlorite?

If you switch to liquid chlorine (aka bleach) you should not have the pH drop.

 

[JamesW]

It's dichlor, which will lower the pH.

You should be careful not to use too much because it adds a lot of cyanuric acid.

 

[mknauss]

Thanks James ---

You need to test your CYA. If over about 50 ppm, time to drain.

 

[joecooler]

Yes I think it's dichlor: sodium-dichloro-s-triazinetione.

Is cyanuric acid CYA? I did the CYA test in the test kit once, lost site of the black dot well below the 100ppm line, so I definitely have a lot of it. Why is this bad?

 

[joecooler]

I've seen in here about using bleach and I like the idea of saving $, but it skeeves me out a little bit - just seems like it would smell bad and burn the skin! What kind of bleach are you using and where can I get it? I know I'm not supposed to use Clorox or anything else that is used for household cleaning.

 

[mknauss]

If your CYA is that high, you need to drain. See FC/CYA chart. To keep the water sanitary, you need to follow that chart. Above 80 ppm it becomes nearly impossible in a spa.

Chlorine is chlorine. What you are using is Dichlor, which is chlorine and CYA. Bleach is chlorine and water.

Use bleach. Plain. Or get Liquid chlorine (same as bleach) from Home Depot, Leslies, Walmart, etc.

 

[BMK]

I've seen in here about using bleach and I like the idea of saving $, but it skeeves me out a little bit - just seems like it would smell bad and burn the skin! What kind of bleach are you using and where can I get it? I know I'm not supposed to use Clorox or anything else that is used for household cleaning.

Yes, for the uninitiated, pouring straight bleach into your water can be something of a leap of faith. We've all been there. You can relax. I can assure you if you test accurately and add the right type and amount of bleach, you will be very happy with the results. No smell, no skin irritation just clear, sanitized water. Plain bleach and liquid chlorine are one in the same. Test accurately and follow the PoolMath instructions, and you'll be on top of it in no time. Hot tubs are actually quite easy to care for once you have everything dialed in.

 

[joecooler]

OK so it sounds like I need to dump the water as soon as possible. Argh. Regarding using bleach, is plain bleach something I can get at the grocery store? What exactly should I be looking for? I have a jug of generic bleach, says the active ingredients are sodium hypochlorite 8.25% and other 91.75%. NO idea what "other" is. :-( It does say contains no phosphorus.

 

[joecooler]

Bueller? Ferris Bueller? :-D

 

[OTPirate]

Yes, plain bleach from the grocery store. Don't get scented, and check the expiration date.

 

[ajw22]

Stay away from Clorox bleach. Almost all available today says it contains Cloromax Technology whice are polymers you don’t want in your pool or spa water.

 

[joecooler]

Is there a particular reason to check the date - are they frequently expired? If it's past the date what exactly does that mean? Per above, I have a jug of store brand bleach, as far as I can tell it doesn't have any additives, but they don't list all the ingredients. How are you supposed to tell? (btw the jug I have at home has a date from 2016)

 

[ajw22]

The strength of chlorine, even bottled, declines as it ages. It may not be as effective in raising your FC as PoolMath predicts if it more than 6 months old.

 

[joecooler]

Ah, got it. That makes sense. Since I have it, and haven't really used it for anything else (hence the age), would it be OK to use it in small doses w/testing to get my chems where they need to be?

 

[mknauss]

Sure.

The date is not an expiration date, it is a 'born on' date. It will look like 19XXX. The 19 is the year (2019), the XXX is the day of the year. Today is day 37 or 19037.