So what's wrong with ALC = 50?

[Durk]

I've been doing BBB on a plaster pool built in 2004 since 2006. Every year I would go through a big bag of baking soda and a couple of gallons of MA to hold ALC at 70 and keep the pH between 7.6 and 7.8. pH would hit 8.0 and I'd knock it down to 7.5/7.6 and then I'd need some baking soda.

This year I decided to do an experiment. After opening and adjusting to ALC = 70 and pH = 7.6, I just let the ALC and pH alone to see what the 'natural' point was. After a few weeks, it settled at ALC = 50, and pH is rock solid between 7.6 and 7.8. The water is crystal clear and is more 'eye-friendly' than it has ever been. It's stayed right there all summer. My jug of MA and baking soda bag are untouched since May.

The only corrections have come from about three weeks on pucks (in one week intervals) when I was travelling (CYA went from 30 to 40, as planned) and a record amount of NJ acid rain. Our rain is below pH 6.8 and it takes three drops of Taylor Base demand reagent to get to where I can read it. Normally I would use some well water (my metals are zero, and I have to add calcium) but this year I haven't. Well water is pH 7.1, I think.

So, I repeat, what's wrong with ALC = 50 in my case? It seems perfect to me. CSI is at -0.23 which seems fine. Absent any good argument to the contrary, I plan to leave it there.

Full test results, since someone will ask:

FC= 4 (before last night's LC dose)
CC=0
CYA=40
ALC=50
pH=7.7
CH=240
Temp=78°F
CSI= -0.23

Testing done with Taylor K-2006 except CYA which is the larger sample TFT test.

 

[Bama Rambler]

There's nothing wrong with the TA being 50 ppm if it works for you.

I think we tend to put too much emphasis on TA when we should let the pH adjustments decide where the TA should be within reason.

 

[Durk]

There's nothing wrong with the TA being 50 ppm if it works for you.

I think we tend to put too much emphasis on TA when we should let the pH adjustments decide where the TA should be within reason.

Thanks. If pool school were written to allow us to be a little more flexible on TA below 70, I could have saved maybe $20 a year and some hassle by doing this sooner. [Not really complaining, this site has saved me big $$$$.] Of course, it still remains to be seen what happens in a dry year.

 

[linen]

I agree with bama's comments. It sounds like your TA/ph has found its happy place. Do you use borates?

We typically don't suggest TA that low without borates. With low TA, ph can change quite a lot with chemical additions.

 

[Durk]

I agree with bama's comments. It sounds like your TA/ph has found its happy place. Do you use borates?

We typically don't suggest TA that low without borates. With low TA, ph can change quite a lot with chemical additions.

No borates. Never saw the need. Since switching to BBB, I've never seen algae, never done a SLAM or OCLT, or had to b'wash before close. It's a very trouble-free pool since I ditched the pucks in 2006. Sometimes I feel like I'm missing some of the fun that goes on here.

But that's interesting. What's the acceptable TA range if I did use borates?

 

[linen]

With borate use the general feeling is TA down to 50 ppm is acceptable. I am not suggesting you do borates though since it seems like everything is working for you.

 

[Durk]

With borate use the general feeling is TA down to 50 ppm is acceptable. I am not suggesting you do borates though since it seems like everything is working for you.

Agree. I was asking in case next year is dry and things change or for some reason the pH decides to 'unstick' in the future. I'm going to keep things as they are right now for as long as it works.

Sorry I used ALC instead of TA. I made that up when I built my Excel spreadsheet record back in 2007 and it's stuck in my head that way.

 

[Richard320]

That's about where mine stays. When I do a major topoff it goes up to 60ish. pH rise is slower and it helps keep CSI negative, which is important for me because of extremely high CH.

I've never been a huge fan of absolute numbers. Too many people - especially doctors, in my experience - look at a set of numbers and if they're just a little out of the arbitrary range, want to treat it with something.