Both my total alkalinity and my pH seem unstable to me (they're moving around a lot).

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chuckles98103

chuckles98103

Gold Supporter
Sep 1, 2019
22
Seattle, WA
See attached image that shows my test results for the past few days. A couple of things to note:
  1. my pH keeps drifting up .. such that I'm averaging ~3 TBSP of "pH Decreaser" per day.
  2. my Alkalinity keeps decreasing. Prior to the results I'm attaching it began at ~110 and gradually fell to 80.
  3. my pool is vinyl lined and is ~2,750 gallons total.
Is there something funky going on with those two things (pH and alkalinity)?

I see Calcium Hardness being wonderfully stable (as I expect) and free chlorine falling (exactly as expected).

My chemicals are:

A. Clorox bleach for chlorine​

B. BioGuard Balance Pak 100 Alkalinity Increaser​

C. SpaGuard pH Decreaser​

thanks for any thoughts,
--tom

PS: my columns are: "FC = free chlorine, CC = total chlorine, CH = calcium hardness, TA = total alkalinity, pH = pH, CYA = CYA, Sat. Idx. = Saturation Index, as per the Taylor test kit I use, Temp = Temp"

A.png
 
Stop increasing your TA unless it goes below 60.
Stop decreasing your PH until it hits 8

When/if you do need to raise TA, just buy this: https://www.amazon.com/Arm-Hammer-B...=baking+soda&qid=1576030868&sr=8-4&th=1&psc=1 It's the exact same thing you're adding now to increase your TA, but without the pool lingo marketing B.S. additional fee.

When/if you need to lower your PH, use muriatic acid (I buy mine at Home Depot). The stuff you're using adds sulfates to your pool, which might not cause problems, but why add it if you don't need it?
 
thanks Jim, i appreciate the guidance.

three questions:

1. isn't the "ideal" range of total alkalinity 80-120? (and if so, isn't 60 a little low?)

2. isn't the "ideal" range of pH 7.2-7.8? (and if so, isn't 8.0 a little high?)

3. does it matter than my CYA reading is close to zero? (my pool is indoor and has a retractable cover, so it's not exposed to sunlight, nor organic debris blowing ).
 
'Ideal' TA is that which keeps your pH stable. Typically that is anything over 40 ppm or so.

'Ideal' pH is anything in the 7's. Even low 8's if your CH and TA are low.

CYA not only protects FC from UV degradation but also tempers the harshness of the chlorine. Indoor pools should have 20-30 ppm CYA in them.
 
'Ideal' TA is that which keeps your pH stable.
Click to expand...

here's the thing: my pH isn't stable .. it's continually moving up. and so that's sort of the core question .. either (1) why is it moving and/or (2) is there some combination of CH/FC/TA/CYA that'll settle it down?

(it sounds like the guidance is: let it move up .. even to the low 8s .. which is not what my Taylor test kit says).

Even low 8's if your CH and TA are low.
Click to expand...

my CH and TA are high ... suggesting my pH should hold at a value lower than 8.

Indoor pools should have 20-30 ppm CYA in them.
Click to expand...

how can i bump up CYA to the 20-30ppm range? my understanding is that clorox doesn't increase CYA ... so, i'd need to introduce another chemical.
 
You can use dichlor 'shock' or CYA powder to add CYA. Use Poolmath

You CH is low. In the 200's. Only thing elevated pH does is potentially create a condition that scale can form. A pH of 8 or 8.2 with your low CH and a TA under 80 will not form scale.
 
chuckles98103 said:
here's the thing: my pH isn't stable .. it's continually moving up. and so that's sort of the core question .. either (1) why is it moving and/or (2) is there some combination of CH/FC/TA/CYA that'll settle it down?
Click to expand...
a high ta will cause the ph to raise
each time you add acid it will lower ph and ta
each time you add alkalinity increaser (aka bicarb soda from box store) it raises your ta which promotes ph to rise
my pool has been stable with ta at 50 and ph at 7.6 and has not moved in 12 months
as mentioned you need to keep ph in the 7.6-7.8 range just add a little acid as required for ph
and ignore ta, unless it gets down to 40 or you ph swings suddenly
 
That you are putting "ideal" in quotes tells me you are already starting to see the problem: the supposed ideal ranges are causing less-than-ideal results.

The short of it is that the numbers in the test kit are just boilerplate numbers found on every test kit, piece of pool equipment, and chemical label. Taylor didn't put any work in to developing them, they just slapped them on and sent them out the door. The truth is that there is no one-size-fits-all TA number, a lot of variables factor in to what TA level creates the most stable pH value. In a larger pool with little aeration and using acidic forms of chlorine (common trichlor tablets are highly acidic) then keeping TA over 100 is usually ideal. In a smaller pool with more aeration and using a pH-neutral chlorine source the TA can and should be kept lower to prevent constant pH rise.
 
You CH is low. In the 200's. Only thing elevated pH does is potentially create a condition that scale can form. A pH of 8 or 8.2 with your low CH and a TA under 80 will not form scale.
Click to expand...

this is incredibly helpful. i included that Sat. Idx. number for a reason .. i've been paying close attention to it, because as my pH rises, i get closer and closer to the high end of the recommended saturation index range - and that's allegedly where scale will form.

that's my underlying concern for trying to maintain the pH.

do you recommend i bring the CH up? and if so, to what? my pool isn't made of masonry .. it actually has no contact with stone, concrete, grout, etc .. and so i don't think it's leeching minerals out of anything (but i could be wrong).

(and thank you!)
 
keeping TA over 100 is usually ideal. In a smaller pool with more aeration and using a pH-neutral chlorine source the TA can and should be kept lower to prevent constant pH rise.
Click to expand...

this is really helpful. my pool is small, indoor, and has almost no direct sunlight exposure .. and my sanitizer is clorox.

so i'll let TA fall until it's more like in the 50-60 range and see if that stops my pH drift.

i'll also add in a little CYA to stabilize the free chlorine .. but i'll likely keep this very low, at around 20.

... and yes, i'm using the wrong pH decreaser and TA increaser .. i'll switch. i was told, by my local spa company, when i bought my pool: "You can't use Clorox or Arm & Hammer Baking Soda in your pool because they contain too many random impurities that will end up in your pool .. you have to use only the chemicals we recommend". i switched to Clorox after reading articles on TFP and will let those other [SpaGuard] additives run out then buy baking soda and muriatic acid.
 

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Does the label on your Clorox bleach say "Cloromax Technology"?
Click to expand...

it does, on the side. (see attached image)

the image of the bleach that's the target of your "Clorox Germicidal Bleach" has the Cloromax logo on the front ... but when i look at it on amazon, it doesn't (the label on the bottle is totally different) .. it says "Now concentrated" with a yellow banner on it:

Amazon.com: Clorox Germicidal Bleach, Regular, 64oz Pack of 1 Bottle: Health & Personal Care

Buy Clorox Germicidal Bleach, Regular, 64oz Pack of 1 Bottle on Amazon.com ✓ FREE SHIPPING on qualified orders
www.amazon.com

it looks like the product i'm looking for is "Clorox Germicidal Bleach, Regular"


IMG_9394.jpeg
 
Thanks, I will check the link. Clorox often seems to change things and you have to watch closely what you are buying from them.
 
chuckles98103 said:
do you recommend i bring the CH up? and if so, to what? my pool isn't made of masonry .. it actually has no contact with stone, concrete, grout, etc .. and so i don't think it's leeching minerals out of anything (but i could be wrong).
Click to expand...
No. Any Ch high enough to keep your water from foaming is fine. That is normally 50 ppm or so.
 
chuckles98103 said:
i included that Sat. Idx. number for a reason .. i've been paying close attention to it, because as my pH rises, i get closer and closer to the high end of the recommended saturation index range - and that's allegedly where scale will form.
Click to expand...
Be ware of using the Saturation Index. It is not designed for pool systems. It is for steam boilers
Use CSI -- calculated in Poolmath. See Calcium Saturation Index (CSI) - Trouble Free Pool
 
chuckles98103 said:
... and yes, i'm using the wrong pH decreaser and TA increaser .. i'll switch. i was told, by my local spa company, when i bought my pool: "You can't use Clorox or Arm & Hammer Baking Soda in your pool because they contain too many random impurities that will end up in your pool .. you have to use only the chemicals we recommend"
Click to expand...
That's a new one. Think of it this way, would you rather put Arm & Hammer baking soda in your pool, or bake with TA increaser! I'll pick the one that is "pure" enough to eat.
 
I went to both Home Depot, Fred Meyer, and Lowe's and found the following:
  1. any/all "Clorox Germicidal Bleach" has Cloromax Technology in it (see image), so i can't use that.
  2. the closest i got to a candidate for "pure bleach" was "Clorox Splashless Formula" (see image) .. but "formula" suggests it has something other than bleach in it (it didn't have a "Cloromax Technology" logo on it, which is good).
  3. the Home Depot product listed on the TFP "Liquid Chlorine" page (HDX 128oz Chlorinating Liquid 3 Pack) is not available anywhere in WA State, according to the folks at Home Depot.
  4. the Lowe's product listed on the TFP "Liquid Chlorine" page (Kem-Tek) is not available.
So that begs the question: what do you 'all recommend for a liquid-bleach equivalent for my pool?

(amazon to the rescue?!?)

2019.12.11-pool_clorox_germicide_homedepot.jpg

2019.12.11-pool_clorox_splashless_homedepot.jpg
 
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Do not use 'Splashless' bleach -- that has polymer in it.

HDX
121 oz. Germicidal Bleach
The Home Depots' in Seattle show availability for this product. It will be located near the cleaning products. Last strength reported was 8.25%.
 
Do you not have a pool store in Seattle that would have liquid chlorine? If not, I have seen people using Walmart/Great Value brand generic bleach.
 

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