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Why do I have high Cyanuric acid in Bromine Spa?


spanewb
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19 minutes ago, dlleno said:

The level of hybobromous acid generated by ozone from bromide is so low that most dont even know that it happens.  Even under no load, ozone will just barely "keep up" with natural sanitizer decay in a clean spa.   Mine won't go above 1ppm.  If left alone, 30ppm will naturally decay asymptotically over a few days (meaning it gets close but won't get to zero). Its a great vacation plan!

Yes sodium hypo is net pH positive.   

Thanks! Being net positive then are you finding you have to add PH down regularly to compensate?

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3 hours ago, dlleno said:

Yes sodium hypo is net pH positive

That was the impression I had as well. I know that pools running liquid chlorine also run acid or CO2 on an automated, sensor controlled system. However, the chemical gurus on several forums, including @waterbear, all agree that liquid is net acidic, in spite of having a high ph in concentration, due to the hypochlorous acid produced in solution or the sanitation byproducts resulting from interaction with organic contaminants. 

Likewise, dichlor, which is listed to be only slightly acidic, is said to be very acidic, and a significant ph drag in the water. 

I have stopped arguing about it myself. The experts all say that the education and info I have picked up over the last quarter century in this business is flawed and incorrect, and the industry training, health department regulations, and CDC guidelines are wrong. So every pool and spa professional out there is doing everything wrong, because we were taught to do so.

Now I try to stick to repair and equipment questions and leave the chemistry to those who know more about it than I.

 

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2 hours ago, RDspaguy said:

That was the impression I had as well. I know that pools running liquid chlorine also run acid or CO2 on an automated, sensor controlled system. However, the chemical gurus on several forums, including @waterbear, all agree that liquid is net acidic, in spite of having a high ph in concentration, due to the hypochlorous acid produced in solution or the sanitation byproducts resulting from interaction with organic contaminants. 

Likewise, dichlor, which is listed to be only slightly acidic, is said to be very acidic, and a significant ph drag in the water. 

I have stopped arguing about it myself. The experts all say that the education and info I have picked up over the last quarter century in this business is flawed and incorrect, and the industry training, health department regulations, and CDC guidelines are wrong. So every pool and spa professional out there is doing everything wrong, because we were taught to do so.

Now I try to stick to repair and equipment questions and leave the chemistry to those who know more about it than I.

 

+1 dude!  I quit digging into the chemical engineering thing too...and just stick with what i observe. If pH is high i add acid lol 

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This is great info. I picked up on the bleach/dichlor method here a couple months ago and applied it to my bromine spa (already added NaBr at last refill and also was using BCDMH tablets plus dichlor as needed for first month). I wanted to slow the TDS rise rate and not pollute the water with excess CYA and also the DMH from tablets. Although my water is crystal clear and smells good after 3 months (credit the ozonator mostly), a couple questions have arisen.

In a bromine spa, do we need to be concerned with buffering our bromine like a chlorine spa? Dichlor hydrolyzes to chlorine and CYA in equilibrium and we get the buffering effect of residual CYA going forward. On the flip side, if one were to start up their tub using bromine tablets (bromo chloro dimethylhydantoin, BCDMH) that result in bromine, chlorine (reactivating bromine), and residual delivery molecule DMH in a similar fashion, then it seems there would also be a parallel equilibrium situation where the DMH is buffering the free bromine. This leads me to wonder if I should start up my spa with NaBr (bank) and bromine tabs first and then switch to bleach after a couple weeks (similar to dichlor/bleach method). Is raw/unbuffered bromine even a concern like unbuffered chlorine is to spa covers and swimsuits?

How do we know bromine is not buffered by CYA? Both the dichlor and bromine tablets proceed with releasing their chlorines and bromines through the same hydrolysis process with the spa water, just different delivery molecules, and it seems plausible. Just trying to make sure we aren't missing a critical issue with operating bromine spas. CYA and maintaining the corresponding appropriate chlorine level is quite a hot topic recently.

Thanks all!

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Yeah, I think that's a good plan to start up with dichlor either way. I don't know what the burn up rate is of my bromine bank due to the ozonator, so if I ran low without knowing, it would be very good to have some chlorine buffering. I may also run a week or two with bromine tabs to build up DMH to a low level...I suppose though that bromine based SWGs don't mess with that, so maybe it's really not a concern.

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