Trichlor tabs

[dalehileman]

Trichlor tabs dispensed near the surface drastically shorten the life of a plastic solar cover and so I have taken to simply throwing the tabs into the water where they alight on the bottom of my inground pool. Our friendly local pool store advises against this owing to the effect of acid these tabs evidently contain but of course they have an agenda, they want to sell you a dispenser

And of course they also want you to come back next season for a new cover, at a cost of $100-$200 each time

If indeed the tabs are acidic, the effect can't be very pronounced as they don't seem to affect Ph. I reasoned that besides, a tablet wouldn't spend more than a day at one spot since my Polaris 380 occasionally nudges it to a new local. However they evidently leave traces on the bottom in the form of geometrical patterns: At the deep end for instance I now have a one large perfect brown square, evidently marking the area of greatest trichlor concentration

If this coloring were the only effect of the tabs I might tolerate it as in the remaining 20 years I hope to live it might save me $4000 replacing the solar covers; but still I harbor trepidation. Google yields some 10,000 hits on the subject, a discouraging prospect and besides most of these also pursue an agenda. Therefore can anyone authoritatively comment on the effect of these tabs at the bottom of a fiberglass pool: (1) Will they really eventually eat through the bottom within my lifetime; and (2) If not, what can I add to bleach the brown stains

By the way I am [email protected] (and apparently don't care who knows it) Thanks all

 

[JasonLion]

Trichlor tablets are acidic. Leaving them sitting directly on the fiberglass will eventually cause damage. The damage is slow and may not be obvious for some time, especially if the pool cleaner is moving the tablets around, but it will accumulate over time and eventually cause serious problems.

If you want to continue using trichlor, your best bet is to get an inline tablet feeder installed. However, you should keep in mind that trichlor constantly raises the CYA level. Eventually the CYA level is likely to get too high and cause problems. Liquid chlorine/bleach is usually the best source of chlorine, since it doesn't add anything that might cause problems.

Using trichlor will lower both your PH and TA. If your TA starts out fairly high this effect may not be obvious for some while, since high TA will raise the PH and the two effects can mostly cancel out.

Brown stains on fiberglass are usually iron stains. Try holding a vitamin C tablet against one of the stains for 30 seconds and see if that helps. If it does, you can use an ascorbic acid treatment to remove the stains.

 

[tgramm]

As a pool professional I would never put tabs of anykind on a pool surface fiberclass or plaster. On occation we've put them on the anti-vortex covers where there is no risk of them moving off but that practice is watched very carfully and only to sanitize the joints of the cover where normal circulation of pool chlorine is poor.

Brown stains? "Bleaching" isn't the solution, brown generally means a ferious metal has been oxidized in that area. Chlorine will only make them worse. Hydrochloric Acid will generally remove them but its a local application that needs to be done, there is an "underwater acid wash kit" that is great for minor stains like this. But you really need to find the source of the stain, generally from firtilizer or (on plaster pools, a shallow rebar tie).


I would strongly suggest getting a tab floater, even if it stays in one spot under your cover. Best solution would be an offline tab feeder or saline system.

As for the chlorine destroying your cover? If its a bubble type cover, high chlorine levels will accelerate its decay but 90% is just old fasion UV damage. I've never seen one last more than a few years even in ideal conditions.

Hope this helps.

 

[Guest]

The tabs are extremely acidic and will damage the gelcoat over time.
The stains sound like iron stains, you can remove them with ascorbic acid but that is a whole procedure! See pool school.
Bubble covers do not last for more than a season or three. That is normal for them. Tp prolong their life be sure to keep them covered with WHITE plastic or a WHITE sheet when off the pool or rolled on a reel.

You might not see the trichlor dropping your pH but it is consuming your TA and once the TA drops too low the pH WILL crash.

Also, for every 10 ppm of FC added by trichlor you are also adding 6 ppm of CYA so sooner or later you will end up with an overstabilized pool and need to drain and refill.

 

[dalehileman]

Thanks guys. Gee but I get discouraged by it all, you either have to be a chemist or hire a maintenance service at some outrageous cost

 

[Guest]

Thanks guys. Gee but I get discouraged by it all, you either have to be a chemist or hire a maintenance service at some outrageous cost

Not really, you just have to become an active member on here. The learning curve is not that steep!

 

[X-PertPool]

Are brown stains always iron? Because according to a rep from united chemical over-chlorination can leave stains too, which would explain why he has a perfect brown square on the bottom of his pool. This would also coincide with what I have seen, Aqua genie's with trichlor tabs laying the the dispensing trays turn brown after a while and whenever I'm at a pool doing some kind of service and the owner asks why his steps are brown I ask if they are using anything but tri-chlor but they only use tri-chlor. Vitamin C takes the stain right off as well. If it is from over-chlorination wouldn't this make sense since tri-chlor is 90+%

Let me know what you think

 

[Guest]

Are brown stains always iron? Because according to a rep from united chemical over-chlorination can leave stains too, which would explain why he has a perfect brown square on the bottom of his pool. This would also coincide with what I have seen, Aqua genie's with trichlor tabs laying the the dispensing trays turn brown after a while and whenever I'm at a pool doing some kind of service and the owner asks why his steps are brown I ask if they are using anything but tri-chlor but they only use tri-chlor. Vitamin C takes the stain right off as well. If it is from over-chlorination wouldn't this make sense since tri-chlor is 90+%

Let me know what you think

No, particularfly if ascorbic, citric, or oxalic acid remove the stain, That is pretty much identification of iron stains. High chlorine levels do play a big part, however! Iron has different oxidation states (the number of electrons attached to the iron ion). Some are colorless and some are colored. The oxidized ones are colord and the reduced ones are colorless for the most part. We all know oxidized iron as rust which is just different iron(III) oxides and oxide/hydroxides and that have yellowish, brownish or reddish colors. Chlorine (hypochlorite) is an oxidizing agent (electron receptor)so it can and will convert the iron ions into colored form (by taking an electron from it and being reduced to chloride ion in the process), which will often precipitate out of the water as stain. If the iron stays dissolved the water colors yellow to brown. The three organic acids that are commonly used for stain control in pools (ascorbic, citric, and oxalic) are all reducing agents (electron doners) and can covert the colored form of the iron ion back into the colorless one by giving an electron to the iron.
Even though trichlor is a chlorinated isocyanurate the ionic species that exist in the water are hypoclorous acid, hypochlorite ion and chlorinates isocyanures, same as for any chlorine source with stabilizer present in the water be it trichlor, dichlor or CYA and any of the following-sodium hypochlorite, calcium hypochlorite, lithium hypochlorite, chlorine gas, or a SWG. The hypochlorite levels in the vicinity of a trichlor tab that is in faily still water (such as sitting on the pool floor ) will be very high. This means staining is more likely.

 

[anonapersona]

Thanks guys. Gee but I get discouraged by it all, you either have to be a chemist or hire a maintenance service at some outrageous cost

Or, better yet, know where to find a chemist that knows all about pools (like here) and pay attention to their advice.

 

[dalehileman]

Are brown stains always iron? Because according to a rep from united chemical over-chlorination can leave stains too, which would explain why he has a perfect brown square on the bottom of his pool............

Let me know what you think

I think you're right about that since the bottom was perfectly clean for 11 years until I began depositing the tabs at the bottom

Inventors alert--

In summary and at risk of repetition it therefore seems obvious somebody ought to market a dispenser that would either sink or float but which would hold the tabs well away from the bottom or top respectively. As I suggested earlier--since it would maximize this separation from both surfaces--someone ought to invent a pressure-sensitive dispenser--much higher-tech and so more expensive of course--by hovering halfway between

 

[PaulR]

Trichlor tabs dispensed near the surface drastically shorten the life of a plastic solar cover and so I have taken to simply throwing the tabs into the water where they alight on the bottom of my inground pool. Our friendly local pool store advises against this owing to the effect of acid these tabs evidently contain but of course they have an agenda, they want to sell you a dispenser

I am thinking you could deliberately park a floater (cheap) by a return jet, or maybe put the trichlor in a plastic mesh bag (cheap) and hang it near a return. If it's under water and away from the sides and floor, the locally high acidity shouldn't be so much of a problem, particularly with the circulation from the returns.

If indeed the tabs are acidic, the effect can't be very pronounced as they don't seem to affect Ph.

Back when I used tabs all the time, I didn't have to worry about the pH. Now I use bleach and I have to put in acid probably every couple of weeks. There's an effect, although it might not be huge.
--paulr

 

[Guest]

Are brown stains always iron? Because according to a rep from united chemical over-chlorination can leave stains too, which would explain why he has a perfect brown square on the bottom of his pool............

Let me know what you think

I think you're right about that since the bottom was perfectly clean for 11 years until I began depositing the tabs at the bottom

Please re read my post above to understand WHY local high chlorine levels lead to bronw stains (from iron!)
You are right that the high local levels of chlorine are causing the stains but they are metal stains, not chlorine stains.

 

[dalehileman]

"I am thinking you could deliberately park a floater (cheap) by a return jet, or maybe put the trichlor in a plastic mesh bag (cheap) and hang it near a return."--Paul

Thank you for that suggestion, it seems like the only practical alternative--at least until the pool industry begins to hire engineers with original ideas

 

[Guest]

"I am thinking you could deliberately park a floater (cheap) by a return jet, or maybe put the trichlor in a plastic mesh bag (cheap) and hang it near a return."--Paul

Thank you for that suggestion, it seems like the only practical alternative--at least until the pool industry begins to hire engineers with original ideas

Why not develop and patent it yourself. It could be the next big thing and make you a millionare!
Then again, trichlor is not the best method of chlorinatin for most people since it does lead to overstabilziation in the vast majority of pools. It is a very small minorty that are able to use trichloro for extended periods without problems.

 

[dalehileman]

"Why not develop and patent it yourself. It could be the next big thing and make you a millionare!"--anonymous contributor

As an erstwhile inventor I can testify that virtually nobody is interested in a new invention. Formulate a substitute for gasoline that is non-polluting at 6 cents a gallon and it will be rejected resoundingly at every turn--especially if is of--say--a strange color. But you're welcome to my idea for what it's worth, good luck marketing it

"Then again, trichlor is not the best method of chlorinatin for most people since it does lead to overstabilziation in the vast majority of pools. It is a very small minorty that are able to use trichloro for extended periods without problems."

Yes, every year it's a new problem but if you take it to your friendly local pool store you can bet they have a solution--at a price. Evidently if you dispense the tabs at the top it ruins your solar cover prematurely (to the delight of the Pool Establishment of course) but if you just throw them into the water consensus has it that they will eventually eat though the bottom. Forgive if I repeat myself but has anyone actually tried this latter approach and if so how long does it take to eat clear though

Pushing my 80th year and supposing you are unsuccessful developing the hovering dispenser this is a question of the most vital importance

 

[Guest]

Evidently if you dispense the tabs at the top it ruins your solar cover prematurely (to the delight of the Pool Establishment of course)

Here is your error, a solar cover will degrade just as fast in a pool that does not use trichlor. The fastest degradation of solar covers is from UV light. If you get two seasons out of a 12 ml cover you are doing great! The thicker covers are not worth the money since they usually only last about three seasons and if you read the ridiculous warranties they are prorated, only warranty about seam separation, and viod if you use chlorine to sanitize your pool! In other words, they warranties are a joke and 12 mil covers seem to give the best value per dollar spend. Solar covers are a consumable commidity, not a one time purchase so get used to it.

 

[dalehileman]

"Here is your error, a solar cover will degrade just as fast in a pool that does not use trichlor."

Exactly what they (the Pool Establishment) want you to believe but which my experience over some 12 years seems to contradict

"The fastest degradation of solar covers is from UV light. If you get two seasons out of a 12 ml cover you are doing great!"

Indeed UV figures into its degradation but the trichlor evidently hastens its demise. In every case the 12-mil cover it lasted only 1-3 seasons but always disintegrated at the shallow end where my tabs were situated

Hence I am very suspicious of any advice originating in the Pool Establishment; present company of course excepted

"The thicker covers are not worth the money since they usually only last about three seasons and if you read the ridiculous warranties they are prorated, only warranty about seam separation, and void if you use chlorine to sanitize your pool!"

So it would seem. One year I paid over $200 for a 15-mil cover with a 12-year warranty in which there was no mention whatever of Cl concentration. It lasted one season, disintegrating at the shallow end just as every previous cover had. When I complained to the supplier they required a specimen to determine the cause of failure upon receipt of which they dispatched a message indicating my warranty wouldn't be honored because of "excessive" chlorine even though its concentration was normal; at least at the deep end where I made the weekly Cl measurement

"In other words, they warranties are a joke..."

Amen

Edited for Politeness by moderator

 

[Guest]

My point, and you missed it, is that the same degradation of covers happens in pools THAT DO NOT USE TRICHLOR! My pool had never seen trichlor or dichlor and I am lucky to get two seasons from a 12 mil cover.
IT HAS NOTHING TO DO WITH TRICHLOR BEING ACIDIC! IT'S FROM THE HIGH LOCAL CHLORINE CONCENTRATION. Even if the chlorine is being dispensed by a peristaltic pump you will see degradation of a solar cover over time.

My question to you is how many solar covers have you seen on pools that were not chlorinated with trichlor and how long did they last. I have seen many.

As far as a non acidic chlorine source, well there are three that come to mind, sodium hypochlorite, calcium hypochlorite, and lithium hypochlorite. Cal hypo is available in tablet and capsule form, btw. However, it does requrei a special vented feeder.

Edited for Politeness by Moderator

 

[anonapersona]

Pushing my 80th year and supposing you are unsuccessful developing the hovering dispenser this is a question of the most vital importance

Hovering...

So take a sealed plastic ball, rubber beach ball or similar, or better yet a tether ball (seen in elementary school yards) or lane divider pool float. Tie it to a rope as long as the deep end is deep. At the middle add an open plastic container, maybe 3" PVC drilled with holes and ends capped. Then add another rope 2 feet shorter than your deep end. Add a good weight to it that is not metal, maybe a pool toy of some sort, heavy enough to not drag around easily. Let ball float on surface with tab holder suspended at middle depth of deep end secured by weight on the end of the rope.

I'd think that having chlorine in the deep end would be very important, closer contact to more water than the shallow end.

 

[dalehileman]

"IT HAS NOTHING TO DO WITH TRICHLOR BEING ACIDIC! IT'S FROM THE HIGH LOCAL CHLORINE CONCENTRATION. "

My bad, of course it's the chlorine which however tends to concentrate around one's tabs. As I had situated them at the shallow end (in the skimmer outlet) and because the cover disintegrated first at the shallow end I concluded that the cover might have lasted at least one more season if I could move the area of concentration away from the shallow end

If I could thus make each cover last just one more season, over the period I hope to live I might save as much as $4000. Unfortunately the Pool Establishment considers as wealthy anyone who elects to possess an inground pool and hence it considers that sum relatively paltry. Besides it's happy to sell that many more covers

So I just throw them in the deep end because so far if this is really risky I haven't yet heard a truly authoritative opinion how long before they presumably eat a hole in the bottom. So I hope to outlive it. If not then I shall fill it with dirt and convert it to a flower garden

Meanwhile though I suspect the Pool Establishment is devoid of such capabilities I'm hoping some forward-looking young engineer markets a tab dispenser that floats halfway between the top and the bottom

But thank you most kindly for your response to my plaints