How does algaecide affect R-0014 performance?

[DeptOfMeteors]

In a desperate effort to deal w/this neverending algae problem, I asked the pool store's advice and one of their recommendations was to put 500mL of algaecide over 24 hours. When I test for pH, and I first drop the reagent in the container, it turns yellow which appears make the pH 7.2, but it's a much darker yellow than the guide. By the time I get upstairs to ask my wife for a second opinion, it turns to a dark magenta, indicating well above 8. No, it's not a matter of changing lighting conditions. When I return to the scene where I started the test, it stays the high pH colour. I've run the test twice.
The FC is a little higher than normal but only about 7ppm, so my best guess is that the algaecide is interfering w/the R-0014.

 

[ajw22]

There are many different products labeled as algaecides with different chemicals.

Post pics of the label showing the ingredients in the algaecide you sued.

Algaecide - Further Reading

www.troublefreepool.com

 

[Mdragger88]

Please understand that Algaecides are at best a preventative- they do nothing for an active algae problem. The only algeacide recommended here is polyquat 60 & then it is only as a preventative/insurance. Most others have side effects . The answer to algae is the SLAM Process.

Algaecide - Further Reading

www.troublefreepool.com

Did u complete your SLAM Process until u passed All 3 end of slam criteria?

 

[Bperry]

In a desperate effort to deal w/this neverending algae problem, I asked the pool store's advice and one of their recommendations was to put 500mL of algaecide over 24 hours. When I test for pH, and I first drop the reagent in the container, it turns yellow which appears make the pH 7.2, but it's a much darker yellow than the guide. By the time I get upstairs to ask my wife for a second opinion, it turns to a dark magenta, indicating well above 8. No, it's not a matter of changing lighting conditions. When I return to the scene where I started the test, it stays the high pH colour. I've run the test twice.
The FC is a little higher than normal but only about 7ppm, so my best guess is that the algaecide is interfering w/the R-0014.

If there was algae need more chlorine in the pool not algicide.

 

[DeptOfMeteors]

I've been spinning my wheels SLAMming for weeks now. I started looking for other solutions.
Another measure the pool store recommended was to lower my sky-high pH, which they said was 8.1. It looks like the answer was somewhere among applying algaecide and muriatic acid, because I woke up this morning and only found traces of algae (and it was probably only a matter of what I missed the night before). Mere SLAMming didn't get me anywhere, although, I've been doing that as well.
But I'm wondering how to interpret my current pH tests and what could be causing these colours.

 

[Bperry]

I've been spinning my wheels SLAMming for weeks now. I started looking for other solutions.
Another measure the pool store recommended was to lower my sky-high pH, which they said was 8.1. It looks like the answer was somewhere among applying algaecide and muriatic acid, because I woke up this morning and only found traces of algae (and it was probably only a matter of what I missed the night before). Mere SLAMming didn't get me anywhere, although, I've been doing that as well.
But I'm wondering how to interpret my current pH tests and what could be causing these colours.

A pH of 8.1 is not sky high. Mine sits at 8.0 for a while before I lower it. You’de be wise to stop listening to the pool store. Your poolmath logs only show a single test result that doesn’t look like SLAM level chlorine. Do you have some test data you can share so we can provide advice?

Algaecide doesn’t stop an algae outbreak once it’s already started.

 

[DeptOfMeteors]

The store said that my high pH inhibited the effects of chlorine. If they were giving me bad information, it's quite the coincidence that the algae finally disappeared when I followed it.
The PoolMath logs just indicate what metrics I felt like logging when I logged them. The data I can give you is that I measured the FC a few times a day, and topped up the chlorine in the morning and the evening. I was previously vacuuming the algae to waste, but the last few days I've been just brushing it. This means I've probably dumped the equivalent to a good 50L of 10% chlorine (although it's probably more like 60L.)

 

[JamesW]

When I test for pH, and I first drop the reagent in the container, it turns yellow which appears make the pH 7.2, but it's a much darker yellow than the guide. By the time I get upstairs to ask my wife for a second opinion, it turns to a dark magenta, indicating well above 8.

That effect is from chlorine, not poly 60 algaecide.

 

[reggiehammond]

The store said that my high pH inhibited the effects of chlorine. If they were giving me bad information, it's quite the coincidence that the algae finally disappeared when I followed it.
The PoolMath logs just indicate what metrics I felt like logging when I logged them. The data I can give you is that I measured the FC a few times a day, and topped up the chlorine in the morning and the evening. I was previously vacuuming the algae to waste, but the last few days I've been just brushing it. This means I've probably dumped the equivalent to a good 50L of 10% chlorine (although it's probably more like 60L.)

Drop based ph testing is inaccurate over FC 10.

 

[DeptOfMeteors]

Drop based ph testing is inaccurate over FC 10.

Then it's not at FC 6? Because that's what mine was when I used the R-0012.

 

[reggiehammond]

Then it's not at FC 6? Because that's what mine was when I used the R-0012.

Oh - I thought you said you’d been maintaining SLAM levels.

 

[Mdragger88]

The FC is a little higher than normal but only about 7ppm

That’s not anywhere near slam level. It’s imperative that you replenish fc to slam level at least 3 or 4 times per day until u pass ALL 3 end of slam criteria. That’s 12ppm if your cya is still 30. FC/CYA Levels
Failing to do so gives algae the leg up everytime fc drops & this makes slam drag on.
Just so u understand- higher fc levels also oxidize polyquat so it won’t quite do what u think & what they probably told u it would do.
There is no magic bullet/potion - slam level fc is the answer.

 

[DeptOfMeteors]

If 12 is the SLAM level, does that mean it should never get below that? If it's not acceptable that it get as low as 6, even for a few hours, then I'm going to have to overshoot 12 by a lot

 

[Mdragger88]

The idea is that the more often u replenish slam level the faster the process goes - the less often, the slower it goes.
Edit: Yes- Every hour not at slam level some algae proliferates faster than it is killed off.
Remaining above minimum fc level for your cya is still killing algae although at a much slower rate. Thus things dragging on.

Overshooting slam level by more than a ppm or two just wastes chlorine to the sun & risks damage to people, surfaces, & equipment. Going over slam level is not advised.

In a perfect world u wouldn’t need to work around life but since that’s not reality & people have jobs…
We often recommend that people start on their day off (like at the beginning of the weekend) so they can hit it hard & dose every couple of hours or so in the beginning as that is when demand is highest. Then maintain the 4x’s a day throughout the work week; for example- upon waking, before work, after work, before bed & at lunch if that’s a possibility.
Often the demand has slowed by then & fc is holding better allowing for longer times between doses.

 

[Bperry]

If 12 is the SLAM level, does that mean it should never get below that? If it's not acceptable that it get as low as 6, even for a few hours, then I'm going to have to overshoot 12 by a lot

Yes, keep it as close to 12 as possible. Overshooting won’t help. And if you’re losing 6ppm in just a few hours, that’s certain evidence you have something consuming chlorine and it’s super important to not let up on the chlorine so the thing eating 6ppm dies.

 

[JamesW]

When chlorine combines with phenol red, it becomes chlorophenol red.

Phenol red C₁₉H₁₄O₅S + OCl^- + HOCl --> Chlorophenol red C₁₉H₁₂Cl₂O₅S + H₂O + OH^-.

Chlorophenol red has a similar color range to phenol red but the colors happen at a lower pH as shown in the chart below.

The pH indicator (phenol red) has reducing agents that should reduce the chlorine at up to 10 ppm.

So, either the reducing agents in the phenol red are compromised or the FC is higher than you think.

 

[JamesW]

Phenol red is a weak acid with pKa = 8.00 (at 20°C).

Chlorophenol red is a weak acid with pKa = 6.0 (at 25℃)

The color change is because phenol red loses protons (and changes color) as the pH increases.

The pKa determines where the protons (hydrogen ions) begin to connect or disconnect from the molecule.

Two Chlorine atoms substitute for two hydrogen ions as you can see in the models below.

It seems that the chlorine oxidizes the carbon from -1 to +1 where it connects.

Phenol red C₁₉H₁₄O₅S




Chlorophenol red C₁₉H₁₂Cl₂O₅S

 

[DeptOfMeteors]

So, either the reducing agents in the phenol red are compromised or the FC is higher than you think.

So either my R-0014 is bad or the chlorine test reagents are? Why not both? I guess it's not a big jump to believe that. So far all the other data I have has turned out to be wrong, why not this? The only thing I know for sure is what's growing on the bottom of my pool for the last several weeks.
However, I did do the test a day later, when the chlorine did test above 10ppm and the colour changes stopped. This time is held steady at 7.2 for several minutes. I realize this doesn't clear up anything. It's just confirmation that this job has been like watching a David Lynch movie.

 

[Mdragger88]

How old are your reagents? Most will last 2 years if stored properly (cool, dry, dark place). If u are getting consistent readings based on your dosages it is unlikely they are bad.
The oto test (while not super accurate) can help reaffirm the results of the fas/dpd test. The ph test can change color if left alone a while. There are several different factors involved in how quickly this may occur.
For this reason it is recommended to read all tests immediately, record the results, then discard the sample.
Here’s some good info on common testing errors as well as how to identify bad reagents

Water Testing Errors - Further Reading

www.troublefreepool.com

 

[JamesW]

To confirm chlorine interference, you can add a drop of thiosulfate to the pH test sample to neutralize chlorine before adding the phenol red.