Pool store recommending pH minus and Stabilizer

[Diy_guy419]

Hi guys,
I just got my pool installed about a month ago, and I have been trying to do accurate tests.
I wanted to compare mine to the pool store, so I took in a sample.
They ran my sample through the spin touch photometer (i think that's what its called, but its a machine that your insert a disk into with your water sample in it).
My pool is FG, 17,500 gallons, SWG

Here are their results:
pH: 8.3
FC: 2.3
TA: 99
TC: 3.1
CH: 136
CYA: 5
Salt: 3500
Phosphate: 0

Their recommendations:
2.5 pounds of pH minus. (I have some muriatic acid, I am going to use that instead)
4 pounds of Stabilizer, I bought the 4 pound powder from them. They said to add it to the skimmer, but I read about the sock method, and I will try to use that.

What do you think?

 

[mknauss]

What are your test results? We do not provide guidance based on pool store tests.

pH minus is dry acid. Not good if you have any metal (including a SWCG). The sulfates will corrode the metals and destroy a SWCG.

 

[Diy_guy419]

I'm not sure if I did mine correctly.
I have the Taylor 2005 kit.
My results are in the pic.

 

[mknauss]

Why are you unsure you did yours correctly?
You do need a FAS-DPD test for FC to improve the accuracy of that test.
Lower your pH to 7.4 using muriatic acid.
Have you ever added any CYA? If not, add 30 ppm CYA worth of stabilizer using the sock method.

 

[Diy_guy419]

I've never added CYA.

How do i calculate what 30ppm is? The whole bottle of 4 pounds?

Side question, how do you measure out liquid acid? Measuring cup? That stuff seems dangerous.

Thanks

 

[wayner]

I have a glass pyrex measuring cup that I only use for pool chemicals. I use that to measure out the amounts of acid. It is dangerous, but just be very careful. I carefully dump the acid in the water and then rinse the pyrex in the pool water to get off any remaining acid.

 

[mknauss]

Use PoolMath for volumes.
In your pool, the 4 pounds you bought will add 27 ppm CYA to your water. Add it all via the sock method. You should get at least 8 pounds more as your CYA should be 70 ppm for a SWCG - Recommended Levels

You have a large pool, so you do not really need to measure the acid that accurately. To lower your pH to 7.4 from 8 with a TA of 130 you need 39 oz of 31.45% acid. So add about a quarter of the jug.

You should wear eye protection when handling acid, but beyond that it is not that dangerous.

 

[Diy_guy419]

Thanks guys,

Love this forum

 

[wayner]

Hi guys,
I just got my pool installed about a month ago, and I have been trying to do accurate tests.
I wanted to compare mine to the pool store, so I took in a sample.
They ran my sample through the spin touch photometer (i think that's what its called, but its a machine that your insert a disk into with your water sample in it).
My pool is FG, 17,500 gallons, SWG

Here are their results:
CYA: 5
...

As an aside, is it even possible to measure a CYA level of 5? With the disappearing dot method you would need about a tube about 100 yards long. I strugle to tell the difference between 40 and 50 - when the dot disappears is kind of subjective. Are there other tests that are way more accurate? What would be the margin of error on their measurement?

 

[mknauss]

As an aside, is it even possible to measure a CYA level of 5?

No. Pool store testing. Enough said.

 

[mguzzy]

I have a glass pyrex measuring cup that I only use for pool chemicals. I use that to measure out the amounts of acid. It is dangerous, but just be very careful. I carefully dump the acid in the water and then rinse the pyrex in the pool water to get off any remaining acid.

NOOOOOOOOOOOOOOOOOOOOOOO! Don't use glass by the pool. Glass and water have about the same index of refraction.. so if you broke it near the pool and it got in the water the only way to find it is in your foot.

Personally I dispense directly from the jug to cut down on the number of transfers from one container to another. I measured out how much 1 quart, 1 pint. 1cup is with an empty jug and now I jut put tick marks on the out side of the jug. I pour to the mark and the old mark becomes the new starting point for the next time.

 

[wayner]

OK, then get a plastic measuring cup like this. I also need very small volume amounts to add to my jacuzzi, like 15-50 ml that is equivalent to a tablespoon or three. Eyeballing from the jug won't work for that.

 

[joboo7777]

No. Pool store testing. Enough said.

This may be incorrect. If the pool store is using a Lamotte Spintouch which is NSF L1 certified it can measure CYA as low as 5ppm.

I would suggest you go to NSF.ORG to get the details on which companies share this certification. Taylor drop test kit is another.

 

[BassPlayingDude]

Even if the machine is capable of that kind of accuracy, I seriously doubt that most pool store employees have the diligence and training to achieve it.

 

[magiteck]

Even if the machine is capable of that kind of accuracy, I seriously doubt that most pool store employees have the diligence and training to achieve it.

As evidenced here... Op states CYA was never added to the pool. If that’s correct, 5 couldn’t have been an accurate result.

 

[BassPlayingDude]

Here at TFP, we believeth not in ghosts nor ghouls nor goblins nor gremlins nor will o'-the-wisps nor alien intervention nor magic pool-store potions, nor midnight chemical additions by mischievious gnomes or sasquatches, nor phantom CYA.

We believe in science.
Hallowed be thy test kit.

 

[BassPlayingDude]

It is by testing alone I keep my pool in ordnung.
It is through titration and colorimetry the reagents acquire speed,
the vial acquires hue,
the hue becomes a warning.
It is by testing alone I keep my pool in ordnung.

 

[YippeeSkippy]

I've never added CYA.

How do i calculate what 30ppm is? The whole bottle of 4 pounds?

Side question, how do you measure out liquid acid? Measuring cup? That stuff seems dangerous.

Thanks

You asked how to calculate what 30ppm is.... The answer is POOLMATH! Either the App PoolMath. or if on your computer (which is me) I use the old classic web version of PoolMath PoolMath

Next you need to buy the missing FAS-DPD tester to get the right FC and CC numbers- FAS/DPD Chlorine & CC's test

Maddie

 

[joboo7777]

Even if the machine is capable of that kind of accuracy, I seriously doubt that most pool store employees have the diligence and training to achieve it.

Here at TFP, we believeth not in ghosts nor ghouls nor goblins nor gremlins nor will o'-the-wisps nor alien intervention nor midnight chemical addition by mischievious gnomes or sasquatches, nor phantom CYA.

We believe in science.
Hallowed be thy test kit.

Ha.. I would agree. The NSF is a reputable organization. In fact most in not all municipal watersheds are testing our drinking water using equipment that is NSF certified. This is not science? Do you think they are using drop tests?

Not trying to argue for the sake of arguing. Maybe more of a healthy debate? these digital testing devices have gone through the same testing and certification process that the Taylor drop test kit has. In fact, the science behind it says they are certified to read CYA(and other parameters) to L1 which is higher than what Taylor provides.

What am I missing? Is it the pool store person administering the test? Is this the issue? Let’s assume they know what they are doing. If the NSF has certified the Lamotte for L1 accuracy and the Taylor drop test for L2 is that enough science?

The aquarium industry is a great example of a multi billion dollar industry embracing digital testing. Many reef keeping hobbyist have gone digital years ago. They are relying on digital test kits from Industrial systems and Lamotte to maintain parameters that require a smaller margin of error than pool parameters. Quite honestly, I was very surprised to hear the pool industry was still stuck on drop test. But then I realized it’s not the entire pool industry. It’s really just at TFP. Yes, drop tests work ok. I still use them. But so does consumer grade digital testing equipment There has to be a reason why TFP is stuck recommending drop tests??


getting ready for my beat down in 3..2..1..

 

[mguzzy]

getting ready for my beat down in 3..2..1..

Ok.. I'll take the first volley...
How much do they cost? At TFP we want everyone to test their own water... and we are asking them to plop down 100 clams to buy a TF100 or equivalent. Can one of these gizmos be found a garage sale for that price... I THINK NOT!... And we would ALL have to have one so we can be on the same platform for discussing results..

I'll let the others hit you with another pillow