Pool Chemistry Mystery

I'm not familiar with the indicator chemicals commonly used to make a visible indication of chlorine levels in pool water. Do you know what chemical (not a brand name) is used?

Assuming that your test is accurate, have you checked the water usage at the pool site? You may have a pool that is getting constantly refilled with fresh water to replace water lost.

Hey Red; I don't know the test/titration chemistry, but they are common pool tests purchased over the counter at any pool store. The pool is filled with well water, but there aren't any leaks ,so water loss isn't an issue. The well water has been in the pool for months...Thanks matt3477

If you maintain pools on a regular basis you can smell the chlorine when the level is sufficient, not that this is an accurate way to maintain the chlorine level, but I can smell mine and come pretty close, actually right on usually....So how does it do on the smell test?

What is thee PH of your pool ?

What is the TA of your pool ?

Before you can see residual chlorine (that which is picked up by the cl2 tester) you must overcome chlorine demand.

Chlorine is absorbed by organics, minieral....... That the water is clear means nothing.

pH and water temperture has an effect on the chlorine demand as well.

Suggest to prove all of your senses, take a gallon of the water and add a cap-ounce-table spoon..........etc. of chlorine, wait a few and test with the cl2 tester.

Keep doing this till you see a residual reading and then take the count of application and divide it by your volume of pool water.

This will give you and indication of how much you have to apply for the "first" application. Should not be as much in later application...........Hope this helps.

Around here the 'well' or spring water is high in minerals, hence 'mineral' water,

A post above says minerals absorb the chlorine.

You say it is well water.

Your chlorine is being absorbed by the minerals in the well water. ??

cnc jim

You may need to super chlorinate (shock) the pool to release the chlorine already in suspension if the hardness is too high.

The two main things to check besides Cl is pH and temp. Both will affect the type of Cl you are using. The higher the temperature of the pool will cause the Cl to form HCl acid which will not be indicated on you meter as stated before you need a meter that can determine between free Cl and Cl compounds. HCl is what causes the sting in you eyes bleaching of you clothes, but has no disinfecting properties.

This is the main reason not to use it in a spa or hot tub.