Water Chemistry Question

[Marty Weinhous]

Here's my problem…

I have tried to maintain a balanced pool with target values of FCL 3 ppm, pH 7.5, TA 90-100 ppm, Ca Hardness 200 ppm, and CYA under 50 ppm. Been failing to meet the CYA target and am running more like 90 ppm.

Prior to around August 2019 my pool's pH would routinely creep downwards and I would correct with pH increasers.

In around August 2019 I switched brands of 3" trichlor tablets. Ever since then the pool's pH creeps upwards. This is contrary to everything I've read. What am I missing?

Thanks in advance.

 

[Marty Weinhous]

My pool's CYA measurements are around 90 ppm. If I have to I'll drain 70% or so and refill. Several products are advertised as "cyanuric acid reducers" and seem appealing. I've tried one with no success. Are any of these known to actually work?

Thanks in advance,

 

[mknauss]

Welcome to the forum!
The CYA reducers do not work. You can search the forum -- they were tried a couple years ago and with proper testing, showed they did not work.
Check the tablets you are using now that you are seeing a pH rise, are they Calcium Hypochlorite or Trichlor?
I suggest you read ABC's of Pool Water Chemistry.

 

[Marty Weinhous]

Welcome to the forum!
The CYA reducers do not work. You can search the forum -- they were tried a couple years ago and with proper testing, showed they did not work.
Check the tablets you are using now that you are seeing a pH rise, are they Calcium Hypochlorite or Trichlor?
I suggest you read ABC's of Pool Water Chemistry.

Thanks for your thoughts.

For both pre and post August 2019 I used Trichlor. The only change was the brand.

Will look at ABC's of Pool Water Chemistry.

 

[mknauss]

Odd on the trichlor. Check for other ingredients. Some have baking soda in them to keep the TA from crashing.

 

[Marty Weinhous]

Odd on the trichlor. Check for other ingredients. Some have baking soda in them to keep the TA from crashing.

They are In The Swim 3" Chlorine Tablets. The technical Specifications from their web site are:

• In The Swim 3” chlorine tabs compare to Bio-guard, Sun, Guardex and Pace.
• One 3” Tablet of Trichlor delivers approximately 5.495 ppm of available chlorine and 3.27 ppm of Cyanuric acid into 10,000 gallons of water.
• Trichlor contains 54.2% by weight of the chlorine carrier molecule Cyanuric acid, so every tablet of trichlor contains 4.336 oz of Cyanuric acid.
• Powerful 90% available stabilized chlorine.
• Slow-dissolving, long-lasting chlorine works great in floating feeders or almost any automatic chlorinator.
• Tabs are individually wrapped.
• Approximately 100 tabs per 50 Lb bucket.
• 99% Trichlor-S-Triazinetrione.

No mention of baking soda (perhaps in there as a binder and not listed?).

 

[mknauss]

Sounds good. Monitor your pool water chemistry.

 

[Marty Weinhous]

Sounds good. Monitor your pool water chemistry.

Oh I do Have been using a Taylor K2005 test kit. With its reagents expiring, I've got a K2006 on order. (That upgrade gets me a color-change titration for the chlorines rather than a color match - much more accurate. Am considering an electronic pH meter to get away from that color match. Are you able to recommend a make/model electronic pH meter?)

 

[mknauss]

Many members have pH meter. I do not. I find the K1000 color match to be very accurate.