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Author Topic: Chemistry Issue  (Read 6838 times)

socal147

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Re: Chemistry Issue
« Reply #15 on: May 27, 2011, 09:48:22 am »
Warranty....Hmmm. After running my spa for over a month using ChemGeeks advice, I have come to a conclusion, be it right or wrong. Manufacturers are using unrealistic and unneeded chemistry guidlines as a way to void warranties. There is no other explaination for requiring this:

Step 2: Adjust the CH to 150-200 parts per million (PPM).

Step 3: Adjust the Total Alkalinity (TA) to 125 to 150 PPM


My spa does not any grout or concrete for the water to attack. A TA  of 125 to 150 makes pH adjustment difficult at best. A CH of 150 to 200 is for what? I keep my TA at @50 and my CH @125. Add the prescribed amount of Gentle Spa. pH stays from 7.4 to 7.8 depending on whether I use Dichlor or MPS to sanitize post soak.

The proper pH range for a spa is 7.4-7.6. I would like to see how one can keep pH in such a tight range. Instantaneous and continuous pH monitor of some type perhaps. B.S. Another way for the manufacturers to say, sorry you voided your warranty.

Amazingly, I can now move pH without the added step of adding pH Up or pH Down. My chemistry is good and my water feels great. I have yet to try the Bleach Method because I am lazy.
 
Adding unneeded chemicals and playing chemical catchup.... a thing of the past.

So, I might take a hit from some saying I am being negative towards the dealers and munufacturers. But there is no other explaination for such water chemistry guidelines.
Thanks Again Chem Geek. Your advice made my spa experience so much easier.

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Re: Chemistry Issue
« Reply #15 on: May 27, 2011, 09:48:22 am »

chem geek

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Re: Chemistry Issue
« Reply #16 on: May 28, 2011, 12:20:57 am »
I really don't think it's that sinister.  I think the recommendations are a combination of two factors.  First is that Dichlor-only use, especially when also using MPS as an oxidizer/shock, is net acidic so needs a somewhat higher TA level for a stable pH (50 ppm would probably be too low in this case and the pH may drop instead of rise). However, they are taking the pool recommendations and not accounting for the higher aeration in the spa, especially when jets are used.  The 125-150 ppm TA isn't the common recommendation -- it's normally more like the 80-120 ppm range typically used for pools -- but of course you are looking at a specific recommendation that is clearly bad.

The other factor is that the people who really understand this stuff are deep in the bowels of some of the manufacturers and even then there may be some manufacturers that have no one that understands the TA/pH relationship that well.  Many of these companies are really just reformulators or repackagers and not real innovators so they don't always have top-notch chemists who understand this stuff (not that it takes high-powered chemistry to understand this -- TA/pH is something one would expect undergraduate students to understand when looking at "systems" involving air/water exchange).  I don't think it's intentional, but rather momentum of hearsay in the industry.  By the time the information trickles down through manufacturer's reps and distributors to spa stores and eventually to the consumer, it's often misinterpreted or misused.

Anyway, thanks for the compliment.  Regardless of the "why" for this poor information about keeping high TA level, I think we're in agreement that the correct information should be told -- namely, that if the pH tends to rise over time, then the TA level is too high because TA is a SOURCE of rising pH in its own right.
« Last Edit: May 28, 2011, 12:23:26 am by chem geek »

footie

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Re: Chemistry Issue
« Reply #17 on: May 28, 2011, 07:48:28 am »
If pH keeps rising then simply lower your TA, it's that simple. If TA at 100 is giving you a ph of 7.8 then drop your TA to 80 and see what happens. I test my pH 2 to 3 times a week and now test my TA weekly.

I do agree that tub manufacturers and chemical companies have got together and are suggesting levels which make you constantly adjust and re-adjust that leads to excessive chemical use, much the same as washing machine/chemical suggestion.

A really good Dichlor/Bleach method worth following is this one

http://www.poolspaforum.com/beta/forum/index.php?s=7a4167e2b878c2e47aaa3b3565f456bb&showtopic=23090&view=findpost&p=96176

Lowering Total Alkalinity

http://www.poolspaforum.com/beta/forum/index.php?s=f2ec3624c9effbd4356563bfdd7889e3&showtopic=19149&view=findpost&p=76819



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Re: Chemistry Issue
« Reply #17 on: May 28, 2011, 07:48:28 am »

 

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