Subject: Re: PSA: Best free no-registration no-ads outdoor-pool-chemistry calculator app/web

Maria Sophia wrote on 3/6/2026 6:15 AM:

PSA: Best free no-registration no-ads outdoor-pool-chemistry calculator app
??? For Windows, iOS & Android
??? No advertising (except they may suggest their own chemicals)

Just some myths that are perpetuated by lack of chemistry knowledge...
a. "1-3 ppm FC is ideal" -> False once CYA exists in an outdoor pool
b. "Shock weekly" -> Unnecessary if FC:CYA is maintained correctly
c. "Algaecide/phosphate-remover prevents algae" -> False; FC:CYA does
d. "Stabilizer should be 30-50 ppm" -> False; FC should be ~7.5% of CYA
e. "pH must be 7.2-7.6" -> False; pH has almost no effect on sanitation
f. "TA must be 100-120" -> False; LSI/CSI is what matters
g. "CH must be high to protect plaster" -> False; LSI/CSI is what matters
h. Low pH causes itchy eyes -> False; chloramines cause itchy eyes
i. Too much chlorine has that YMCA smell -> False; chloramines do that
j. Add acid to counteract bleach high pH -> False; it self-balances in
hours
k. FC is the best measurement of sanitation -> False; ORP is
l. Trichlor "pucks" are great -> False; they raise CYA & lower HOCl over time
m. TDS is an important measurement -> False; it's mostly a measure of
water age
n. "High CH causes scale" -> False; CSI determines scale, not CH alone.
o. Filtration is mandatory -> (debatable); I never run my pumps & my
water is fine
p. Pump mixing is mandatory -> Not with bulk mixing from wind, temp,
motion, density
q. Any other myths?
Swimming season is coming up (at least here in California), and what
I've found, over the years, is this is the only known pool calculator
app that is a. Free
b. Registration free c. No ads (although every calculator suggests their
own chemicals)

Web:
<https://www.orendatech.com/pool-dosing-calculator>
Android: <https://play.google.com/store/apps/details?id=com.elitecrest.orenda>
iOS:
<https://apps.apple.com/us/app/orenda/id1171005221>

It's not just the individual calculations that matter, but what matters
is almost every pool-chemistry advice on the web is dead wrong in many
ways.

There are only two calculators on the planet, that I am aware of, which
are correct, and one of those requires you to log into their web site. Having said that, both provide free online advice, which is kind of nice
of them.
This TFP calculator is also correct, but it requires registration (AFAIK).

Web:
<The old 'PoolMath Web' calculator is gone; replaced by PoolMath Pro> Android: <https://play.google.com/store/apps/details?id=com.troublefreepool.poolmath>

iOS: <https://apps.apple.com/us/app/pool-math-by-troublefreepool/id1228819359>

As far as I'm aware, no other pool calculators available to the public
are correct.
But I could be wrong, so please let us all know if you know of better calculators.

Thanks. Maybe you should do a tutorial on the subject?



--- PyGate Linux v1.5.12
* Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)