Defective K-2006 Kit?

[droweye]

I just got my K-2006 kit yesterday. I have tested my pool yesterday and today with similar results.

My tests show:
FC: 15 ppm
pH: 7.8
TA: 125 ppm
CH: 600 ppm
CYA: 180 ppm
first test covered black dot way below 100 ppm reading, so i made a 1:1 mixture of tap water and pool water got a reading of 90
Temp: 60 F from SWCG diagnostics

Local pool store test:
FC: 5.2
Using K-2005 kit, I asked him how he knew it was 5.2 when the maximum on the color guide is 5, he said that the color would be deep purple if it was above 10 ppm and it was only a slight shade darker than 5.0
pH: 7.5
TA: 110
CH: 410
CYA: 30
I'm not even sure if he tested CYA, last time I went it was 35, how did it go lower?
Phosphates: 200 ppb
I stopped using Phosfree last week

My Pool Specs:
20,000 Gal Plaster
Hayward Swimpure with 40k+ Cell
1.5 hp Whisperflo pump
Cartridge filter

So my question is. is my K-2006 kit from VM Innovations defective or is my local pool store being dishonest?

[PoolDoc]

So my question is. is my K-2006 kit from VM Innovations defective or is my local pool store being dishonest?

Your results look pretty typical to me.

DPD color match tests for chlorine are not reliable AT ALL above 5 ppm. Pool store CYA testing is notoriously unreliable.

You can get real world confirmation by
(1) buying a cheap OTO / phenol red test kit at Walmart as a back up kit (good idea, anyhow) -- 15 ppm will be dark yellow in OTO, but you'll need to let it sit for 2 minutes or so.
(2) consider your chlorine loss rate -- with CYA = 180, your chlorine should be dropping maybe 1 ppm per day, assuming you are NOT swimming in it. (Body goo, etc will consume chlorine, but you should be losing very little to sunlight.)

After you confirm both your FC and CYA levels, you need to look at the best guess chart, linked in my signature. You'll need to avoid doing anything to raise your CYA, and you'll need to keep your chlorine levels very high, to compensate for the high stabilizer. The Best Guess page explains all that.

[droweye]

Is high CYA levels harmful for my SWCG? Manual tech specs suggests 60-80ppm.

[Watermom]

You need to follow your manual's suggested levels for CYA levels. I think 60-80 is pretty typical for most SWCGs.

[PoolDoc]

Hmm-mmh. I guess that would be a good idea, Watermom. But, is there any reason to think that high CYA will *hurt* his SWCG?

I was thinking, he could simply adjust chlorine levels upward, and let his CYA levels 'run down' over the season, unless he has a reason to do a partial drain and replace.

[PoolDoc]

Hey All;

I checked with all the moderators and contributors -- heard back from PoolSean with AutoPilot and Chem_Geek. They are both pretty sure high CYA is NOT a problem for SWCGs. So, I'm taking that as authoritative

Of course, all other conditions of high CYA still apply, primarily that you have to follow the levels shown in the Best Guess Chart, and you'll need a K2006 or other DPD-FAS kit to test.

[droweye]

Thank you for all the feedback! I guess for the time being, I'll run the pool as it is and maintain the best guess FC level. I'll let the CYA decrease on its own or drain a small portion for the summer to lower CH.

[PoolDoc]

That'll work.

Two cautions:

1. If you take your water to be tested by a pool store that can accurately measure either your FC or CYA levels, they will freak out, and give you dire warnings that you'll soon get hairy palms, that your great-grandmother and great-niece will surely die of instant cancer of the toenail and nasal hair, and that your garden plants will mutate and eat you. Ignore them.

2. If you get algae, you will either have raise your chlorine VERY high . . . and it will stay there for weeks OR you'll have to use a lot of polyquat ($$$) or you'll need to add a small amount of sodium bromide. Your best option: maintain circulation and chlorine and don't get algae. Second best: sodium bromide in as small amounts as possible. I'll cover this option before summer.

[droweye]

Will adding some Borates be a better alternative over sodium bromide and polyquat? I've been reading through the guides which suggests that bromine interferes with chlorine chemistry lowering its effectiveness and that "once a bromine pool always a bromine pool" until you drain and refill.

[waterbear]

2. If you get algae, you will either have raise your chlorine VERY high . . . and it will stay there for weeks OR you'll have to use a lot of polyquat ($$$) or you'll need to add a small amount of sodium bromide. Your best option: maintain circulation and chlorine and don't get algae. Second best: sodium bromide in as small amounts as possible. I'll cover this option before summer.

I would not recommend the sodium bromide. Some SWCG cells don't like it! Another option si 50 ppm borate.