Swimming Pool Chemistry - Lowering TA/pH
 

Why is the "slugging" method of getting muriatic acid into a pool used
to lower TA and why is "broadcasting" used to lower pH. In other
words, what happens chemically when a product is slugged into a pool as
opposed to sprinkling it all around. One would think that the end
state is the same.

One would think that the end state is the same.

Unless one thought that reaction kinetics varied with pH in the reactants,
and pH being a measure of dilution/concentration. Adding 10 units of 0.1M
acid is not the same as adding 1 unit of 1.0M. Dilution, or promoting
faster dilution by broadcasting, matters.

Whether it matters in the superstitious minds of pool technicians versus
the reality of a pool, with these particular reactants, is another
question.

Unless one thought that reaction kinetics varied with pH in the reactants,
and pH being a measure of dilution/concentration. Adding 10 units of 0.1M
acid is not the same as adding 1 unit of 1.0M. Dilution, or promoting
faster dilution by broadcasting, matters.


That makes sense, thank you for the answer.

On another matter I would be curious to hear your opinion on the
suggested practice by the industry of superchlorinating a pool every
week. Actually the interval varies depending on who you talk to. I am
under the impression that if you maintain your ORP at 650 then this is
not needed, upsetting the pool industry because you're not buying
these little bags of 75% cal hypo at 3 times the price of the 70%
stuff in your big bucket.

Paul Giroux writes:

On another matter I would be curious to hear your opinion on the
suggested practice by the industry of superchlorinating a pool every
week. Actually the interval varies depending on who you talk to. I am
under the impression that if you maintain your ORP at 650 then this is
not needed, upsetting the pool industry because you're not buying
these little bags of 75% cal hypo at 3 times the price of the 70%
stuff in your big bucket.

Superchlorination is the best way to clean up accumulated problems.
Residential pools tend to accumulate problems, because they tend to
fall below minimum sanitation at a moment's neglect. Moreover, with
the CYA scheme, there's hardly enough chlorine to keep you from getting
sick, and not enough to keep the pool clean, thus the need for routine
superchlorination.

"Richard J Kinch" wrote in message
. ..
Paul Giroux writes:

On another matter I would be curious to hear your opinion on the
suggested practice by the industry of superchlorinating a pool every
week. Actually the interval varies depending on who you talk to. I am
under the impression that if you maintain your ORP at 650 then this is
not needed, upsetting the pool industry because you're not buying
these little bags of 75% cal hypo at 3 times the price of the 70%
stuff in your big bucket.

Superchlorination is the best way to clean up accumulated problems.
Residential pools tend to accumulate problems, because they tend to
fall below minimum sanitation at a moment's neglect. Moreover, with
the CYA scheme, there's hardly enough chlorine to keep you from getting
sick, and not enough to keep the pool clean, thus the need for routine
superchlorination.

The first season of owning a pool, I used tons of chlorine. Then I found
out about stabilization. This is cyanuric acid. If you don't have it in
the right balance, the chlorine you have leaves through the surface quickly.

Pool stabilizer is about $20. A test kit is about $20. Those buckets of 3"
tablets are about $60 on sale. I have not had to add stabilizer for three
years, except when I drained it for replastering.

When buying those chlorine tablets, look for stabilized chlorine. It stays
in the water longer.

"Shocking", or superchlorination is needed occasioinally, but that chlorine
is unstabilized, so it doesn't keep the high chlorine levels for as long. I
buy the 5 gallon bucket of NASTY granules, and use that about two cups at a
time once a month, or when I need to for heavy use, or the start of algae.
The big buckets are WAAAAY cheaper than those $2 bags.

Just my experiences. Your results may vary.

Steve

SteveB writes:

When buying those chlorine tablets, look for stabilized chlorine. It
stays in the water longer.

Not really:

http://www.truetex.com/poolcontrol.htm

On Tue, 10 May 2005 16:44:54 -0500, Richard J Kinch
wrote:

SteveB writes:

When buying those chlorine tablets, look for stabilized chlorine. It
stays in the water longer.

Not really:

http://www.truetex.com/poolcontrol.htm


Look here http://www.tubgirl.com

"Richard J Kinch" wrote in message
. ..
SteveB writes:

When buying those chlorine tablets, look for stabilized chlorine. It
stays in the water longer.

Not really:

http://www.truetex.com/poolcontrol.htm

Yes, really.

Steve

When buying those chlorine tablets, look for stabilized chlorine. It stays
in the water longer.

And the stabilizer stays in there forever and accumulates until you
reach 'chlorine lock'. I much prefer using cal hypo, that way I can
'manage' the cya myself. I know what's in there right now, nearly 10
ppm and no more. Later this summer I know I'll have about the same
amount. Every evening I do a quick check of the pool and add
chlorine, usually 1/4 cup of 70% cal hypo, about $0.20 a serving.

http://www.truetex.com/poolcontrol.htm

It's been a while since I visited that page, thanks!