How High To Take Cl2 To Break Down Gunk

[waterbear]

How did you get a CYA of 110? The test only goes to 100.

[jereece]

I estimated 110 CYA because it took a little above the 100 mark till I could no longer see the dot.

I think her calcium level was about 140ppm. I believe they are on well water. However they have been using the Trichlor tabs not Calcium Hypochlorite.

Thanks for the validation. I thought it was going to take 20-25ppm to burn off the gunk.

Jim

[waterbear]

the CYA view tube is not marked in a linear fashion. The marking are closer together at higher CYA levels than at the lower ones. This is why the test only reads to 100 ppm. It is too difficult to judge the level when it is higher than that. There is a good possibility that the CYA is much higher than 110 ppm,

You can dilute a water sample with an equal amount of distilled water and test that. Multiply the test results by 2. While you do lose some precision by diluting you will get a better idea of where the CYA is at the present time.

[chem geek]

I estimated 110 CYA because it took a little above the 100 mark till I could no longer see the dot.

I think you meant a little below the 100 mark since above that mark would be between 90 and 100 ppm. The marks go from high (100) at the bottom to low (30 or 20 depending on test kit) at the top.

[jereece]

You are right ChemGeek. On my kit 100 is an inch or so up from the bottom then the measure marks start. And you are right WaterBear the marks are not linear. So I should have diluted. Now, you mentioned using distilled water. Why can't I use tap water? Tap water should not have any CYA...should it?

Thanks guys.

Jim

[waterbear]

Tap water should not have any CYA...should it?

Thanks guys.

Jim

Not unless there is herbicide runoff. However, it's just good testing prodecure to used distelled water for dilutions Tap water can and usually does have chlorine and ammonia in it.

[jereece]

Got it.. As always I appreciate the education.

Jim

[Watermom]

Also, no more trichlor pucks or dichlor powder in this pool. Stick with bleach or liquid chlorine.

(If it was my pool, I do a partial drain and refill to get that cya level down.)