High Alkaline And No Fc?

[Aramei]

I just opened pool last week. I have a 28' x 4.'. We have a Hayward Sand Filter. I don't know what size. I placed enough stabilizer for 20,000 gallons but I'm thinking I may have to add more???

I tested water the other day after running filter. All other levels were fine. My alkaline was high and the FC was down to 0, it also said I had no stabilizer???....any ideas? We use liquid chlorine and have been putting a couple gallons in each night.

I am still a newbie at pool chemistry. I am unsure if the alkalinity level is affecting the FC or vice versa??

Christine

[chem geek]

Christine,

The Total Alkalinity (TA) will not affect the Free Chlorine (FC). If you truly have no Cyanuric Acid (CYA aka stabilizer or conditioner) in the water, then any chlorine will break down quickly by the UV in sunlight. So you should add some CYA to the water, but not too much. If you want to add both chlorine and CYA at the same time, you can use Dichlor powder/granular as your source of chlorine for a time. just keep in mind that for every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.

You can do an overnight test to see if the FC measures shortly after adding it at night (say, within an hour, with the pump running) and then check it in the morning before the sun hits the pool for too long. If you have <= 1 ppm FC drop overnight, then your chlorine loss is due to sunlight during the day. If you have a larger loss at night, then you may also have either algae or ammonia in the pool.

You can learn more about how to manage your pool by reading the Pool School.

Richard