Pool store testing question

[kevinm]

Hi All,

I opened the pool a couple of weeks ago to a green pool with a bit of algae. I guess I didn't keep the chlorine level high enough during the warm fall we had.

After adding bleach, the next day the green was gone and the pool was cloudy. It took about a week to clear it all up. Thankfully, all of the time reading on this forum paid off and I didn't panic. I added about 20 gallons of bleach and 3 gallons of muriatic acid.

The pool is now crystal clear and sparking. I have the 234s test kit and have tested twice now. This morning I took a sample to the pool store to be tested (I needed a part for my heater).

Their numbers were not even close to mine. They tested:

TC 5
FC 5
pH 7.8
Tot Hard 145
alk 85
salt 2500
cya 100

I tested:

TC 7
FC 7
pH 7.6
Tot Hard 210
alk 110
salt 3700 (and my cell reads 3600)

chlorine is still high from all that I added to kill the algae (added too much I guess)

I explained to them that their numbers - especially salt was too low. They the tester and another person who walked up said my cell must be wrong. I explained that I also use a drop test that supported the cell reading.

They completed ignored what I said and told me to add 2 bags of Mineral springs beginnings. I asked if they realized that this was bad advice and would bring the level too high for the cell - blank stare.

They then went on to tell me to add Balance Pak 100 to bring up my alk, I then told them that I should not (and they should not suggest it) add anything given the difference in the numbers.

They then continued to tell me additional items to add. I thanked them went on, but then spoke to the owner and told her I was surprised at their persistence. She agreed I should not add anything (after I convinced her I knew what I was talking about). I had to explain to her the drop test for salt.

Any way, just thought I would add this to further warn others. If I didn't know better I would've spent a couple of hundred on unneeded chemicals, and would be draining and refilling due to high salt.

Any idea why they would be that different on numbers?

It's forecasted to be in the high 80's today - off to the pool (a refreshing 64)

Kevin

[CarlD]

Hi All,

Their numbers were not even close to mine. They tested:

TC 5
FC 5
pH 7.8
Tot Hard 145
alk 85
salt 2500
cya 100

I tested:

TC 7
FC 7
pH 7.6
Tot Hard 210
alk 110
salt 3700 (and my cell reads 3600)


Kevin

They inevitably are testing with strips. You are using FAS-DPD powder. Your TC/FC measurement is more accurate. The pH difference is negligible and I wouldn't worry about the hardness and alk measures. Again, I expect yours to be better.

The ONLY concern I have is the CYA measure. You need to do your own because if 100ppm is correct, you need to RAISE your FC to a minimum of 8 and a maximum of 15 for daily swimming--and shock by going to 25ppm.

[kevinm]

Hi Carl,

My CYA is closer to 80ppm. I have a SWG and 80 is the high side of recommended. I typically keep it in between 60-80ppm and I keep my chlorine around 1-1.5.

Kevin

[chem geek]

So with an SWG and a CYA of 80 ppm, you need to have the FC be at least a minimum of 3.6 ppm (4 ppm is a little safer). This is lower than Ben's minimum but we've seen that SWG pools can get away with a somewhat lower minimum due to the more consistent dosing. Definitely only having 1-1.5 is taking a chance for algae to grow unless you are lucky and have low nutrients (phosphate or nitrate) or are using a supplemental algaecide (at extra cost).

Richard

[CarlD]

Kevin,

I must have missed the SWG part. Richard, of course, is right, that lower FC levels work when you have an SWG because there's a constant level of chlorine, not a yo-yo effect you must watch for.

Since you have the SWG, just run at the higher level Richard recommends and you won't have a problem.

[kevinm]

Morning All,

So yesterday, I thought I would give it another try at the pool store since it was raining here (seems like that's all it does) and I thought that I needed some CYA and some Calcium. I have to regularly take water out due to the rain.

Here's their numbers:

CYA 100
TC 2
FC 2
pH 7.8
TA 90 (with adj of 60)
hardness 205
salt 2100

here's my numbers with a 234s kit

CYA 45
TC 4.5
FC 4.5
pH 7.5
TA 80
Calcium 260
Salt 3000


What concerns me is that with the exception of TA, we weren't even close. I test every week and typically pH is the only thing that fluctuates unless I need to drain, which I have. My numbers typically don't change much except for salt, CYA, and calcium have been going down as you would expect. I've added salt.

I also have brought my TA down to 80 based on some of the posts here and at another forum.

I tried to explain that TA acts as a pH buffer and that I have intentionally lowered it. When she went over the list of everything I should buy and add, she commented that, "I guess you don't want to add this to raise your TA. Just be careful that your pH doesn't get to low". I chose to not respond at that point.

My concern, is it possible that my kit has an issue? Especially the reagents for CYA, as I measure it lower than I like to keep it. I don't want to add if it is truly 100. I went through that with salt - adding too much and needing to drain to get it in line, I don't want to repeat.

Thanks,
Kevin

PS. Hopefully we all have a dry and wonderful Father's day.

[waterbear]

You are dealing with a Bioguard dealer. They want to sell as many chemicals as possible.

Their ALEX testing system is skewed to sell as many chemicals as possible.
It is also strip based.
To give you an idea of how sleazy they are their balance pack100 will say it's sodium hydrogen carbonage which is just another name for sodium bicarbonate but if you try and tell them that they will SWEAR you are wrong and that sodium hydrogen carbonate is different and why balance pack is better than baking soda.

Believe your own testing.

If you really want to stir up somethng ask about CYA. They will tell you that up to 200 ppm is fine (as will all of Chemtura's companies and dealers including Omni, Sun, Guardex, Pooltime, and Aquachem in addition to Bioguard.)