chlor tabs on fiberglass

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
dalehileman

chlor tabs on fiberglass

Postby dalehileman » Sat 25 Jul, 2009 12:35

Chlorine tabs dispensed near the surface drastically shorten the life of a 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

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

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 the tab at the bottom of a fiberglass pool

Incidentally one tablet doesn't sit long a a specific spot since my Polaris 380 occasionally nudges it to a new location.

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


chem geek
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chlor tabs on fiberglass

Postby chem geek » Sat 25 Jul, 2009 13:50

Trichlor pucks/tabs are very acidic and will certainly cause problems with most any pool surface. I put a Trichlor puck at the bottom of my plaster pool to see if a stain was metal or organic and it left a noticeable puck mark where the plaster was essentially acid washed. For vinyl pools, such acidity is the worst thing for the vinyl causing it to weaken and fade. For fiberglass, acid isn't good either. So I agree with the pool store that you should not just leave the puck at the bottom of the pool.

I also agree with you that the pucks have the water near them be acidic and this isn't good for pool covers. In fact, it's bad for pretty much everything. Years ago when I used Trichlor for chlorine, the floating dispenser parked itself near some stainless steel bars we have in our pool and it rusted the mounts closest to the feeder.

If one has to use Trichlor, then the best way is to use an inline chlorinator. A floating feeder would be next best if one can keep it away from walls and have water circulation nearby to prevent too much acid buildup near the surface (i.e. to prevent the cover from wearing). Another alternative is to use the specially designed BioGuard Silk Smart Sticks that can be put into the skimmer (most Trichlor pucks/tabs cannot be put into the skimmer if the pump is ever off since the on/off cycles with built-up acidity are not good for downstream equipment nor for the skimmer area).

Are you not adding pH Up regularly to compensate for the drop in pH over time from the Trichlor? Most pools that use Trichlor find that their pH goes down unless they have a very high Total Alkalinity (TA) with lots of aeration in which case they need to add baking soda over time as the TA drops. If there were no outgassing of carbon dioxide, then 1 ppm FC per day for a week (i.e. 7 ppm FC) from Trichlor would lower the pH from 7.5 to around 7.2 if the TA were around 100 ppm.

Of course, another alternative is to not use the Trichlor at all and instead use chlorinating liquid or 6% unscented bleach. Since you have a pool cover, you could probably just add this twice a week. This will prevent the buildup of Cyanuric Acid (CYA) since for every 10 ppm Free Chlorine (FC) added by Trichlor, it will also increase CYA by 6 ppm. You can learn much more about maintaining your pool at the Pool School .

Richard
dalehileman

chlor tabs on fiberglass

Postby dalehileman » Sun 26 Jul, 2009 15:07

Geek thank you for that rundown. From what you disclose it would seem that they ought to market a tab dispenser that can somehow suspended halfway between top and bottom
dalehileman

chlor tabs on fiberglass

Postby dalehileman » Sun 26 Jul, 2009 15:11

Geek thank you for that rundown. From what you disclose it would seem that they ought to market a tab dispenser that can somehow suspended halfway between top and bottom or one that sits on the bottom but holds the tabs a few inches up
chem geek
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chlor tabs on fiberglass

Postby chem geek » Sun 26 Jul, 2009 19:12

That's a great idea, but it doesn't exist. The closest thing to that is the inline chlorinator plumbed near the pump. Of course, continued use of Trichor builds up the CYA level making chlorine less effective so if you use Trichlor as your primary source of chlorine then without a LOT of dilution of the water you'll need to use a weekly algaecide (e.g. PolyQuat 60) or a phosphate remover to prevent algae growth, and will need to shock the pool and/or use clarifiers to keep the water clear (since the chlorine won't oxidize bather waste, suntan oil, etc. as quickly due to the higher CYA level) or will need to maintain a higher FC level proportional to the CYA level.
dalehileman

chlor tabs on fiberglass

Postby dalehileman » Mon 27 Jul, 2009 10:12

Geek thank you again for your input

chem geek wrote:That's a great idea, but it doesn't exist.


Well, it ought to, seems eminently logical as the need for such a device seems very compelling. Maybe with this discussion someone possessing the necessary credentials might take action. Surely SOMETHING needs to be done

The closest thing to that is the inline chlorinator plumbed near the pump.


Thank you for that suggestion and I will consider it. However it sounds expensive

Of course, continued use of Trichor........you'll need to use a weekly algaecide........


I do dose it once a week with a supermarket algaecide/clarifier.but was just recently horrified to reread the instructions and realize that I wasn't using nearly enough. As a minimum they want us to use 1-2 gallons per week. But I am wondering--since they obviously have an agenda--if that isn't a whole lot more than typically needed

......and will need to shock the pool and/or use clarifiers to keep the water clear.......


Good God but the average pool-owning clod (me) needs to be a chemist. I hate to shock it that often--at least during the summer when we plunge every day

Incidentally the only apparent effect of just throwing in the tabs is to produce brownish geometric patterns at the bottom and if this is the only problem I will live with it as a new solar cover sets us back as much as $200. With a fiberglass pool such as ours, are there more serious signs and if so how do I recognize them
dalehileman

chlor tabs on fiberglass

Postby dalehileman » Mon 27 Jul, 2009 10:20

"Are you not adding pH Up regularly to compensate for the drop in pH over time from the Trichlor?"

Yes but it's not often required, suggesting the "acid" from the tabs isn't as powerful as those with an agenda seem to suggest. I hate to add soda ash more often than necessary because it clouds the water. Sure, my sand filter will eventually clear it but to curtail my electric bill I run it only 3 hours a day instead of the 8 hours urged by those with an axe to sharpen
dalehileman

chlor tabs on fiberglass

Postby dalehileman » Mon 27 Jul, 2009 10:26

Note to Admin: Thank you most kindly for this Help Forum. However I have a couple of suggestions: (1) Provide the wretched participant a means to edit his post without a repetition of its entire text, and (2) The requirement for confirmation code with each posting is a real nuisance, especially for those who are slightly colorblind or who cant tell a cap character from an LC. Other such forums require this only at initial registry
Me...
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Chlor tabs on fiberglass

Postby Me... » Mon 27 Jul, 2009 10:45

You do need to maintain the chemistry in order for it to become easier and less expensive. Letting it get out of hand will lead to more problems that take more chemicals and time to alleviate.

Pucks on the pool bottom will rot, discolor, bleach or in some way ruin that tiny little circle it occupies. The more places they rest, the more places it WILL ruin. Puck erosion feeders are maybe $100 and by far your best option.

Your cover will be ruined also by bad chemistry. If your chlorine is doing double duty trying to compensate for bad chemistry there will be more products of oxidation trying to offgas at the surface than need be. With a cover in place they will gather at the surface under the cover and help to deteriorate it.

A puck feeder that floats halfway might be a danger to swimmers and a nuisance to cleaners. Does your vac stay in the pool a lot? Maybe try and rig a small net as a floater and hook it your cleaner to drag around the pool as it cleans. That would be better then leaving the puck on the bottom.
dalehileman

Chlor tabs on fiberglass

Postby dalehileman » Tue 28 Jul, 2009 11:35

Me... wrote:You do need to maintain the chemistry ........

Pucks on the pool bottom will rot, discolor, bleach.......


Thank you Me for these added details. Discoloration doesn't bother me while the puck won't sit long in one spot since it is nudged around by my Polaris. If rotting somehow proceeds anyhow how do I recognize its onset

And how long might it take to eat clear through as I'm pushing my 80th year and don't expect to live forever. Meanwhile each solar cover as I mentioned runs $100-$200

Puck erosion feeders are maybe $100 and by far your best option.


Forgive my ignorance but is a puck erosion feeder what I had called a dispenser and if it floats on the surface how does one prevent the local concentration that attacks the solar cover

.......products of oxidation trying to offgas at the surface.....and help to deteriorate it.


Forgive me,though I aced college chemistry but you might elaborate. Exactly what would cause the gas and would I see it as bubbling under the cover

A puck feeder that floats halfway might be a danger to swimmers and a nuisance to cleaners.


None of my guests uses the deep end but spend the entire time standing in the shallows sipping their brews. However I hadn't considered a dispenser anchored as you imagine might snag my Polaris. Therefore I propose a high-tech dispenser without chain or other suppotrt that senses pressure allowing it to hover halfway between the surface and the bottom

Think of the opportunity here for the entrepreneur

Does your vac stay in the pool a lot?


All the time except when we're swimming

Maybe try and rig a small net as a floater and hook it your cleaner to drag around the pool as it cleans. That would be better then leaving the puck on the bottom.


That's a very good idea Me, revolutionary. As an erstwhile inventor myself I think Polaris ought to consider it and if they do you should get royalties. However it might meet considerable resistance from the solar-cover makers and others having an agenda within the Pool Establishment who would fight tooth and nail to maintain the status quo. Thank you again Me for your input

Incidentally coincidentally if you wish to discuss this or anything else--like tasting The Brew--I am [email protected] (and apparently don't care who knows it)

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