Bio-Active CYA Reducer trial

[Rflasck]

I started using liquid Clorox when I started the BA-CAR trial. In addition to the CYA results, I’ve noticed a few other “odd” things. I thought I’d ask here, unless you think I should start another thread.

Prior to the trial, I used trichlor pucks. I had to run my FC up to 15- 20 ppm to prevent algae blooms. Once I started the trial I poured in the BA-CAR and started using Clorox on a daily basis to keep the FC between 2 and 3 ppm. I was fearful that I’d have a massive algae bloom, but BA said when using their CAR, algae would be suppressed even at low FC levels. To my surprise, during the trial while running FC of 2 to 3, there was indeed no algae.

Now several weeks after the last bag of BA-CAR was dumped in, with a CYA still over 300, and FC maintained at 3 to 5, I still have no algae problem! The BA-CAR should all be gone now, and my CYA is still high, but I have no algae. The only differences between now and before the trial are:
1) I use to run my PH at 7.2, I’m now running it at 7.7, and
2) I’m using 8.4% Clorox now instead of trichlor hockey pucks.

In the experience of the wise folks on this site, would either of those changes explain the absence of algae in my pool now?

Also, the FC level in my 10K gallon IG pebbletek pool is now dropping about 1.5 ppm per day (I add about 3 cups of Clorox per day on average). We’ve had cool weather, so the pool has not been used much the last 3 weeks. Is that level of chlorine consumption about normal in a pool of my size and low use?

Thanks,
Richard

 

[JasonLion]

No, none of the factors you mention would do it.

I wonder what your phosphate levels are? Very low phosphate levels could account for both the lack of algae and the reason the CYA reducer didn't work.

 

[Rflasck]

No, none of the factors you mention would do it.

I wonder what your phosphate levels are? Very low phosphate levels could account for both the lack of algae and the reason the CYA reducer didn't work.

Interesting.

In past years, I have used the No-Phos pool store stuff to keep my phosphates low. I cannot measure phosphate level myself, so I must rely on the pool store phosphate measurements. Historically, my phosphates have been very low (<100). Just before the trial started, the pool store measured my phosphate to be 0 (zero), which I suspect was wrong since I have not used No-Phos yet this year. After the trial (2 days ago) the pool store measured my phosphates to be 250 ppm, which they consider high. I was going to add a bit on no-phos tomorrow. Do you think I should?

Before the BACAR trial, I read all the BA material carefully. They never said anything about a minimum phosphate level for their BA-CAR to work, so I did not worry about it.

The pool store phosphate measurement of zero 6 weeks ago may very well have been bogus anyway. For a month prior to the trial, I was running FC>15 ppm and was always on the hairy edge of an aglae bloom. I was brushing my pool daily and washing some green algae residue from my cartridge filters almost daily. So before the trial there was certainly enough phosphate for the aglae, so there should have been enough phosphate for the BA-CAR to eat.

Richard

 

[chem geek]

Maybe the phosphate level was high enough for reasonably fast algae growth before but the Bio-Active microbes consumed them for their growth. Unfortunately, they didn't seem to do what they were supposed to which was break down the CYA.

 

[Rflasck]

My second question was whether about 2 to 3 cups per day of 8.4% concentrated Clorox bleach seemd reasonable for my 10K gallon pool with cool weather and low use. Any comments?

Thanks,
Richard

 

[JasonLion]

If the water is below 60 degrees that sounds very reasonable.

 

[chem geek]

That would be 1.1 to 1.6 ppm FC per day. Chlorine chemical reactions on average roughly drop in rate by around half for every 13ºF drop in temperature. So cool water would be expected to not have nearly as much chlorine loss. The loss from sunlight, however, is not temperature dependent so there is a limit to how low the loss rate will go unless the pool is covered or the days cloudy.

 

[Rflasck]

Well, since this IS “the Deep End” forum where “Pondering the deep mysteries of pool chemistry? Plunge into the more technical aspects of pool care” is done, so……..

I’m trying to determine if my high CYA level is 1) lowering my chlorine burnoff to a normal level and 2) why I am algae free with FC=3.5 and CYA=300.

Let me say that yesterday, I was successful in complying with Kalifornia regs and still completed a 20% drain and refill. Indeed, my CYA level immediately went down ~20% (I’m now about 300).

The weather has been cool to mild. Highs around mid 70’s lows in the mid 50s. Pool water temp has remained between 68 and 72 F. Mostly sunny skies with a few passing clouds.

Yes, my daily loss of FC has been about 1.3 ppm per day. That has required about 2.5 cups per day of 8.25% Clorox. From your response, it appears that for my pool, water temp and weather that is about what to expect with normal CYA levels (even though my CYA levels measure about 300).

Moving a bit more into the mysterious…..I have been maintaining a FC level of about 3.5 ppm for over 6 weeks now. My CYA has been around 300+ during that whole time. Before the trial, I was constantly fighting off algae bloom when the FC was kept at 10+ppm.. Now (after the trial and after the start of Clorox use) my pool looks great, and there is no algae anywhere, all while I am keeping the FC level at only 3.5!!

Perhaps I should just thank my lucky stars and not worry about the seeming lack of logical consistency, but I’ve found that that usually comes back to bite me eventually.

Any thoughts?

Richard

 

[chem geek]

I suspect the phosphate level got lowered from the Bio-Active bacteria growth, but that's just a guess. If you were to test for phosphates, we'd know, but that's an expensive test (the Taylor K-1106 is $34) and I don't trust the pool stores to do it right.

 

[JasonLion]

I still think your phosphate level is very low, which would account for everything you mentioned. The pool store phosphate testing is inconsistent, but just as compatible with phosphate being near zero as any other possibility.

 

[Rflasck]

I still think your phosphate level is very low, which would account for everything you mentioned. The pool store phosphate testing is inconsistent, but just as compatible with phosphate being near zero as any other possibility.

OK. Thanks guys! I'll just be thankful that (aside from a high CYA) everything is looking good. If anything changes (like an algae outbreak) I'll let you know.

Thanks,
Richard

 

[heugeneo]

I spoke with several employees at bioactive during my four bag trial and twice I was informed that the product did in fact lower phosphates. I was also told they will be coming out with an algaecide-like product so that's why they aren't advertising that the cya reducer prevented algae growth, as they will have the other product for that purpose.

I've wondered, based on no real knowledge, if people not having decent results from the bioactive is because all the product is used up on phosphates before it has a chance to get to work on the cya?

 

[JasonLion]

The two are intertwined. It binds up phosphates in the process of building the bio catalysts that will break down CYA.

 

[Rflasck]

Update three years later.

At the end of my 2015 BA testing it appeared that the BA was not able to reduce my CYA below 300. I decided to stop the BA trial at that time and just use the pool while keeping all other pool chem levels in the optimal ranges. Now, after 3 years of only using bleach (no hockey pucks) my CYA was about zero. I don't think I had 10,000 gallons of splash out during the last 3 years. I think the CYA slowly decomposed over the 3 year period. Two days ago, I used one hockey puck in the skimmer and the CYA rose to about 50. So I'll continue to use only bleach and continue to monitor my CYA (and all other chem) levels. The take-away: use bleach, not hockey pucks.

 

[tim5055]

Update three years later.

At the end of my 2015 BA testing it appeared that the BA was not able to reduce my CYA below 300. I decided to stop the BA trial at that time and just use the pool while keeping all other pool chem levels in the optimal ranges. Now, after 3 years of only using bleach (no hockey pucks) my CYA was about zero. I don't think I had 10,000 gallons of splash out during the last 3 years. I think the CYA slowly decomposed over the 3 year period. Two days ago, I used one hockey puck in the skimmer and the CYA rose to about 50. So I'll continue to use only bleach and continue to monitor my CYA (and all other chem) levels. The take-away: use bleach, not hockey pucks.

While I agree with your assessment to use liquid chlorine, I don’t think,your CYA was zero. One 8 oz tab would only raise your CYA 1.4 in a 10,000 gallon pool.

My experience was similar to yours, it,took me close to 18 months to get the CYA from around 250 to 50 where I wanted it.

 

[cfherrman]

Cya gets oxidized by clorine slowly, most say 3-5 ppm a month

Good job with both of you keeping a pool clear from 250 cya!