Pool company - their chlorine test vs. mine & CYA

[Carter]

Hi everyone, I have a situation and I'm hoping that someonem might have some insight. I have a pool in N. California. I discovered that my pool company raised the CYA to 100. I was concerned that I'd have to keep the chlorine at about 10ppm, but the pool company says they want it at 5ppm or below. *But*, my Taylor FAS-DPD kit showed 20ppm.

The management acknolwedged that they super chlorinated it for some reason, but it would be safe to swim in it up to 25ppm. A week later, I told them that the levels were still 16ppm+. I asked what reading they had from their recent visit, and the guy told me 3+. Huh? I asked how they could have such a low number against my high reading. He said their kits don't go above 3, but they have fresh reagents, and that my kit might be old. So I could go buy a Guardex kit to compare.

The next time the pool guy came by, I asked him about it. The night before I read 10ppm. He said he read about 3 and showed me his kit. It was an older looking one with yellow gradients, it stopped at 3. He said he can tell when it is higher by the deepness of the color. So, I'm wondering if his kit might only measure active chorine, and thus be correct if the CYA is inhibiting the free chlorine. Or are they totally off? BTW, they are a very established service in the area for the past 30 years.

Any feedback would be great!

[PoolDoc]

Hi Carter;

Dunno if your pool company is ignorant, or just trying to keep from scaring you.

Ok, here goes:

+ "Turns yellow" reagent = OTO, orthotolidine. Your guy can NOT accurately estimate levels using that. Trust your Taylor -- but check the instructions and make sure you are following them.

+ With CYA = 100, 16 - 20 ppm FC should be fine. See Best Guess chart (no longer a guess!) linked in my sig.

+ Out of curiosity, who's your company? Sounds like PoolChlor or one of the other long-time chlorine "shooter" companies. If so, you may have a new guy who doesn't understand everything he's been taught.

Ben

[Carter]

Hi PoolDoc,
Thanks for the quick reply. The company is North Bay Water Services, http://www.nbws.com
The guy who does the pool is in his first year and admits he is facing the challenge of new seasons, but he calls into the office if he needs advice. He seems to take the job very seriously and is trying to predict future chemical demand and understand past results, so I like that.

[PoolDoc]

Ok, interesting -- they are a bleach company -- "liquid chlorine". I didn't know that any of the bleach companies were running high CYA / high Cl pools.

Ben

[Carter]

So they are following the BBB method in a sense?
What do you think about the testing they do - if the tech is using an OTO kit, should I be looking over his shoulder all the time and telling him how much to put in, or just trust them as they tell me to?
Thanks!

[PoolDoc]

2 ?'s

#1 - Depends on what you mean -- CarlD made the name up to describe both the method I developed and the 'Bleach, borax, and baking soda' grocery store chemicals. Others tend to use it to refer to those chemicals specifically. I use it to refer to a general approach of using only what you need, from the most practical sources.

All of the elements of the BBB method, in the sense of referring to the use of those three chemicals, others did first. Combining them in the approach I did seems to have been a first. Someone *may* well have been doing all the same things, but they didn't ever publish it. And all the references I can find to the "BBB method" on the Internet seem to have originated here.

In the larger sense, of the BBB Method referring to my entire approach to pool care, there are some elements that seem to be unique. In particular, I was the first to identify aeration + lowered pH as the only effective method of reducing carbonate alkalinity in pools, and to point out that ALL the information the pool biz published on that point was incorrect. I've been told that people involved in industrial water treatment had been doing that for years, but again, no one in the pool industry seems to have recognized that. And, I've still never seen a published account of that, other than a user's post here, years ago, in which he said he'd been trained to do that.

If you're interested, the intro page to PoolSolutions lists some of the 'firsts' here. But please keep in mind that I consider it probable that someone else may have also discovered some -- or even all -- of these, and had been using them before I did. However, if they did so, they didn't publish it.

#2 It sounds like they may know what they are doing, as an organization. It's very common for service techs to have a wrong understanding of why they do what they do, but to STILL do the right thing. It wouldn't hurt to use a K2006 to check up on them periodically, but I don't know that it's essential. Still everybody works better if they know someone else is watching, even if it's in a friendly way.

Ben

[CarlD]

As Ben says, it's not just Bleach, Borax and Baking soda, it's a method and a mind-set.

It does sound as if your company is actually doing OK. As long as FC is in the "Best Guess" range for CYA=100ppm, it's not a real problem if the kid working the vacuum reads his OTO a bit wrong (Why don't they at least give them Taylor OTOs that read to 5ppm????) Could be worse: He could be using strips. If I were, you, though I'd still check my water, at least every other day.

Using a CYA of 100ppm probably allows them to safely keep their visits down to once a week. At that level, IF you maintain the residual chlorine level (8-15ppm) the FC may well last all week. But your K-2006 gives you peace of mind.

Carl