Liquid bleach vs. Total Dissolved Solids?

[Sumo1]

Since the water temp is<55F, I turned off my SWG and plan to use liquid bleach through the winter. A friend who has a pool service business said bleach would raise my TSD too much and recommended granular. Is he right? I don't know how to measure TSD. I've always gotten by using test strips so I hesitate to post any test numbers.....

[CarlD]

No. He's wrong. Bleach is the simplest and purest method of chlorinating your pool. It has no side effects and the "inert ingredient" that makes up the other 94% is saline solution.
Pool industry folks have been convinced by the pool chem companies that only their products are safe. This is false. Every form of granular chlorine has drawbacks, drawbacks that bleach doesn't have. Tri-Chlor and Di-Chlor both add Stabilizer far beyond what you need, and add acid as well. Too much of either quickly becomes a problm. Cal-Hypo adds calcium, too much of which becomes a problem. Other forms add lithium and cost a king's ransom.

BTW, to further the deception, most pool stores SELL bleach, in Ultra Bleach strength (6%) and in DOUBLE ULTRA strength (12.5%). They call it "Liquid Chlorine" or "Liquid Shock" but it is IDENTICAL to bleach.

We recommend either bleach or Liquid Chlorine as your primary chlorine form, unless you have a salt-water generator.

Total Dissolve Solids is a measure pool stores use to scare customers. While it CAN be a real problem, you only look into it AFTER all the typical solutions to problems don't work. In other words, TDS is something you can safely ignore if you follow our guidelines for pool maintenance. It just will never become an issue--it hasn't for me after 7 seasons, and it hasn't for the other moderators after as long or longer.

The kicker is that granular chlorine and dry acid add FAR more TDS than bleach.

[chem geek]

Carl is absolutely right. [EDIT] Well, no, I was wrong because I didn't account for the salt that is in liquid chlorine due to its production from chlorine gas into a solution of lye (caustic soda). I have corrected the TDS amount below. 12.5% chlorinating liquid is around 125,000 ppm chlorine and around 100,000 ppm salt making it about 3 times saltier than sea water (359,000 ppm is saturated salt water or brine). [END-EDIT] The following table shows the increase in TDS, calcium, and other factors. The TDS is calculated after the chlorine that is added gets consumed (chlorine consumption is an acidic process) and after any base is added (if necessary) to restore pH (the base used is caustic soda -- other bases increase TDS for Trichlor and Dichlor even more).

Increase in TDS, Calcium and CYA with 1 ppm FC increase and usage

Type of Chlorine          TDS  CH   CYA  Acid/Base
Bleach / Liquid Chlorine  1.6  0.0  0.0  Slightly Basic
SWG                       0.0  0.0  0.0  Neutral to Moderately Basic*
Calcium Hypochlorite      1.2  0.7  0.0  Slightly Basic
Trichlor (tablets)        1.4  0.0  0.6  Very Acidic
Dichlor (granular)        1.8  0.0  0.9  Moderately Acidic
Chlorine Gas              1.6  0.0  0.0  Extremely Acidic

*SWG varies in its tendency to increase pH and therefore the amount of acid needed to remain neutral. The pH rise (probably from outgassing carbon dioxide due to aeration from the hydrogen bubbles created in the SWG) and added acid to restore pH will increase TDS, but is not shown above since it varies by pool.

In a salt-water pool using an SWG, the TDS is already high due to the added salt. By using bleach or liquid chlorine you will be adding the smallest amount of TDS and will not increase CH nor CYA and will probably not need to add any acid or base. [EDIT] This is not true because I did not account for the salt that is in the liquid chlorine originally. [END-EDIT] During the winter with cold pool water temperatures, you will be adding very little chlorine, perhaps only 1-2 ppm FC per week (if that much) which means that you will be adding 1.6 ppm [EDIT] NO! actually it's 3.2 ppm [END-EDIT] or less TDS per week or adding only 32 ppm TDS [EDIT] NO! it's 64 ppm TDS [END-EDIT] over 20 weeks. This TDS is actually just salt so is exactly the same as if you added 32 ppm salt to your pool. This is only a 1% increase [EDIT] NO! it's a 2% increase [END-EDIT] in your salt level and you probably will lose at least that much through dilution/overflow.

Richard

[chem geek]

Note that I corrected the previous post. I neglected to account for the salt (chloride ion) that is produced when liquid chlorine is made by bubbling chlorine gas in a solution of lye. So from a total TDS point of view, liquid chlorine isn't better than other sources, but at least all of its TDS is (or becomes) salt unlike some other sources that increase CYA or CH.

[CarlD]

Notice that the BOTTOM line from Chem_Geek is that it STILL doesn't matter.

You'll be backwashing and losing water to other things, reducing TDS.
TDS is only a problem when
a) you HAVE a problem
b) Standard fixes don't work
c) your TDS is high enough to be the culprit.

You may go your entire life (and most owners do) without TDS presenting ANY problem for you.

Pool store owners and workers are inculcated by the chem companies with incorrect and frequently deceptive information.

[Sumo1]

Thanks, Gents!

[socalKC]

With a SWG what is an exceptable TDS ppm reading? What kind of problems result from too high TDS?

thanks,

karen

[waterbear]

With a SWG what is an exceptable TDS ppm reading? What kind of problems result from too high TDS?

thanks,

karen

High TDS does not cause problems in a salt pool if the TDS is from salt! (Unless you have a SWG with a high salt shut off in which case you simply dilute the water in the pool just like you would do if you accidently added too much salt.

[CarlD]

TDS and Phosphates are just the latest scare tactics designed to get you to trust pool chem companies, whose main interest is transferring funds from your bank account to theirs and feed you every kind of BS they can to do it.

[waterbear]

TDS and Phosphates are just the latest scare tactics designed to get you to trust pool chem companies, whose main interest is transferring funds from your bank account to theirs and feed you every kind of BS they can to do it.

TDS has been around for a long time and is usually the reason given for a pool getting algae outbreaks that can't be controlled because of the 'old water' with high TDS. Of course, the CYA level that is through the roof because of the use of stabilized chlorine has nothing to do with it at all!