considering going back to the Dark Side

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twd000

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Feb 19, 2013
137
Tucson, AZ
I have had a lot success and good results using BBB this first summer in my pool

Especially the education and testing knowledge; knowing what is happening in my water, and why.

I have heard and read all the horror stories due to using dichlor and trichlor pucks, and the resulting sky-high CYA.
However, I have had the opposite problem using BBB only, can't keep the CYA up. I have added 2x the calculated amount for my pool in the form of liquid stabilizer over the course of the summer, and it will slowly drop from 70 to 50, then I'll add more stabilizer, etc.

I know the theory says CYA is only consumed by splashout, but that doesn't explain it. I don't know where it's going. It's not a fast drop like the ammonia weirdness I read about.

I fact, I have started using some leftover trichlor pucks in a floater that a friend gifted me, to supplement the bleach. After 2 weeks keeping 3 pucks in the floater, CYA is back down to 50.

I have noticed that my daily bleach consumption has dropped from 3 to 2 quarts, which is nice.

So I'm thinking if I keep up with the pucks, I can cut my maintenance time in half by only adding bleach every other day, instead of every day.

For whatever reason, my pool doesn't seem prone to overdosing on CYA, so why not supplement the bleach and cut back to an every-other-day schedule?
 
+1 what Zea said.

BBB is as much a philosophy educating and understanding as it is anything else IMO. You've got it no matter what you use and that doesn't mean you went back to the dark side. It's all good. Isaac may well be right...I would sure be curious how much water you are replacing.
 
twd000:

Every pool is different, although I would rule out any possible leaks as Issac-1 raised. A quick test you can try to determine whether you have a leak is the Bucket Test. If you do have an auto-fill system, turn it off during this test.

I think there is a misconception that one of the tenets of BBB is, "Thou shalt never-ever-ever use pucks." Trichlor pucks do have their place in pool water management, although for most pools they are not a good long-term solution since they often result in building up CYA to impractical levels. Repeating what Brushpup said just to emphasize the concept: BBB is about having a solid understanding of what parameters to measure in order to properly manage your pool along with knowing what chemicals/dosages are needed and their effect on the water. As long as your pool water parameters are in the recommended ranges, your good to go. I would still determine if you have a leak, though.
 
I guess a leak is a possibility. I don't have an auto-fill; I top it up manually. About every 7=10 days, I put about an inch of water in it. Surface area is roughly 15'x28'. I'll try the bucket test this week.

We also have very high evaporation rates with daytime highs around 105 and 25% humidity. If the water is evaporating, it should also be leaving behind calcium hardness, right? I'll have to go back and check my notes to see how fast CH has been rising.
 
Thanks Bo, I should have elborated more on that.

Yes, you leave behind all minerals when evaporating water. In my business it's called cycling up. Check before re-fill and you will see just how much you are cycling up. Honestly, that doesn't sound like much to lose, but if the auto fill is on you won't really know. Turn it off for the bucket test.
 
Brushpup said:
Thanks Bo, I should have elborated more on that.

Yes, you leave behind all minerals when evaporating water. In my business it's called cycling up. Check before re-fill and you will see just how much you are cycling up. Honestly, that doesn't sound like much to lose, but if the auto fill is on you won't really know. Turn it off for the bucket test.
Click to expand...

I don't have an auto-fill
 

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How often are you back flushing? Other than a leak, or splash out, that's about the only other way you could be lowering the CYA.
 
Leak test and (as long as you are testing CYA and have the latitude in the levels), there is nothing wrong with using pucks for chlorination. When I do a drain and refill, I start with 5lb of CYA, then use pucks to Get the CYA and FC levels balanced, then switch over to the SWG.
 
ping said:
This link, degradation-of-cyanuric-acid-cya-t8880.html, from Chemgeek might be what you are experiencing. Read the portion on CYA Degradation by Oxidation from Chlorine.

I have had to add CYA twice this summer to my pool and I feel this article explains how my pool is losing its CYA. I have been keeping my pool 86-92 degrees this summer and tend to keep the FC on the higher end.
Click to expand...


thanks for the article. It's a bit more chemistry-heavy than I can fully comprehend

my water temperature is 84-88 all summer

would it be better to run lower FC to reduce the CYA oxidation?

Has anyone done the math on a CYA-consuming pool to figure out the cheapest tradeoff of FC?
 
If we go by this statement, "So, assuming a CYA loss rate of around 0.4 ppm/day in our pools this comes to 12 ppm per month which is clearly enough to be noticeable as the months pass during a swim season. If one shocks the pool, then the rate of loss could be about 2-3 times faster. Wojtowicz also shows a strong temperature dependence on the chlorine oxidation of cynauric acid where every 10F increase in temperature results in roughly doubling the rate of degradation. So his data was with pools at 85F so pools at 90F could have degradation rates about 1.4 times higher.", I would say a 10 ppm loss of CYA a month is reasonable in some pools.

I believe my pool has lost about 30 ppm of CYA since my first adjustment to 80 ppm back in May. My June 1st testing of CYA measured 70 ppm, my July 1st test measured 60 ppm, and my August 1st test measured 50 ppm and I noticed a larger demand of chlorine so I bumped it back up to 80 ppm. I have not needed to add any salt as it has been stable at 3400-3500 since May according to my SWG, so I'm not losing a measurable amount of chemicals to water loss.

I don't think you want to run lower, but shoot for the target and don't let it drop below the minimum amount for your CYA. The target amount is a safe amount so that the FC level should not drop below the minimum amount for 24 hours. I run it at the higher end due to the DW teaching little kids for 8 hours a day in the pool which tends to use up the chlorine.
 
My personal experience in my pool that is kept at around 88ºF is that the CYA loss is low at perhaps 3-4 ppm CYA per month, but I have a mostly opaque pool cover. With a pool exposed to sunlight, the loss rate might be faster due to the hydroxyl radicals that are produced when chlorine breaks down. If the loss of CYA is due to oxidation by chlorine (as opposed to water dilution), then a 10 ppm CYA loss in a month would show up as 0.83 ppm FC per day chlorine loss. The rest of daily chlorine loss would mostly be due to sunlight.

For residential spas we've seen roughly 5 ppm CYA loss per month, but spas are often hotter at up to 104ºF, though they are generally covered so not exposed to sunlight.
 

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