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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.....
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.
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).
*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.Code: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
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
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.
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.
Thanks, Gents!
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.Quote:
Originally Posted by socalKC
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!:rolleyes:Quote:
Originally Posted by CarlD
Quote:
Originally Posted by waterbear
Nah, nothing at all--until they say "Oh! You have chlorine lock!" (whatever THAT is--another Never,Never Land term).
No one has applied scare tactics on me, I have no algae out break, nor old water.....I just wanted to know. Maybe not a question that can be answered here... sorry, thought this was the place to ask. my mistake. thanks anyhoo.
K
socalKC,
Please don't be scared away by the sarcasm. The "TDS is bad" line is just common. You wanted information and the answer is that you do not need to worry about the TDS level, but you do need to make sure that your salt level (which really measures chlorides and reports it as ppm sodium chloride) is in the range that your SWG requires (varies by mfg. but usually around 3000-3500 ppm or so).
In a plaster/gunite pool with 100 ppm TA, 300 ppm CH and 30 ppm CYA, then the TDS will be at least 185 ppm above the salt level. Usually, it won't be much higher than that because the main component of TDS is salt.
Richard
The thing we have been trying to say is that the pool industry has blamed TDS for problems in pools that have nothing to do with TDS. I suspect part of that is from the chemical companies that manufacture trichlor because if the word got out that their stabilized chlorine caused the problems in pools it would hurt their sales so they use TDS instead. Bottom line, if you have old water your TDS will be higher than if you have new water. This in itself does not cause problems but if trichlor was used there will also be very high levels of cyanuric acid and that WILL cause problems. If they blame the cyanuric acid it would hurt their sales. The cure for high TDS and high CYA is the same, however...drain and refill!
Don't worry about TDS is all we are trying to say.
Socal, you have us all wrong. We have all seen SO many scams, have had SO many honest but ill-informed pool owners come here and relate the layers of nonsense that they have been fed by pool stores, that I coined the phrase "Pool-Stored" a few years ago for victims who had their pockets picked.Quote:
Originally Posted by socalKC
We don't sneer at people who have been pool-stored, we empathize with them. Most of us have been there. And the weapon to fight back against it with is information and knowledge.
If you haven't been taken or scammed by them, that's really great! You are wisely skeptical enough to protect yourself. That's EXACTLY what we encourage you and all the rest of us to be.
TDS is one of their favorite scare-tactics. I had a guy give the whole song-and-dance a couple of months ago about liquid chlorine adding TDS.
Now LC (bleach) adds a particular TDS--Salt. But years and years of LC use won't add NEARLY as much salt as what is required for a Salt Water Generator. A SWG pool has TDS levels that would make a pool store guy positively DROOL at the prospect. But it's all nonsense--Salt as a TDS is basically harmless until there is SO much that the SWG shuts down.
Phosphates are their other big scam so they can sell phosphate reducer. Lately they even are selling phosphate reduction maintenance plans (like you have with your HVAC guys)!
We have found that simply following good, simple maintenance practices consistently works for pretty most everyone. One in a thousand gets into trouble with TDS or phosphates.
would filling your pool through a water softener give you sky high TDS #'s???
would it be better to bypass the softener and then worry about getting rid of the iron in the fill water? Just wondering what the best route to take would be. Thanks, Eddie
A water softener is just going to exchange one set of ions, such as iron, copper, calcium and magnesium, with another set of ions that are more inert, such as sodium or potassium. Though this technically changes the TDS number due to the differing molecular weights of these substances, in practical terms this doesn't matter.
It's not TDS itself that is any problem, but rather what specifically TDS is composed of that could be an issue. If the TDS is mostly plain salt (e.g. sodium chloride), then this isn't a problem (in terms of corrosion) unless it gets really high, and remember that SWG pools have around 3000 ppm salt. If the TDS is composed of a lot of dissolved organic compounds, then some of these may cause side effects though most do not -- remember that Cyanuric Acid (CYA) is an organic dissolved solid and it affects chlorine effectiveness.
The main thing that filling a pool with water from a water softener does is to add water that is depleted in calcium and is therefore lower in Calcium Hardness (CH). Depending on the type of pool you have, you want some CH (i.e. plaster pools typically have around 250-300 ppm CH). So if you are using the water softener to reduce the iron content of the fill water, you will probably have to supplement the water with additional calcium chloride to raise the CH. That's perfectly fine to do.
Richard
Thanks for the response and the explanation. I am always thinking of different ways to manage my water chemistry to make it easier for me. Without the proper knowledge, I get me nervous if I don't fully understand what I am doing and the consequences that can happen. I would hate to mess something up. Thanks again, Eddie
Richard,
You've posted a lot of amazing posts here over the last couple of years but the one above may well be your best. I don't think I've ever seen you write better or more clearly and concisely. It combines the perfect blend of scientific knowledge and nuts-and-bolts techniques!
Wow!
Carl