I'm confused!!

[CPerry25]

I ran a test with the TF-100 kit on my pool water 3 days ago. Everything looked pretty good with just a little low pH of 6.9, and the FC was at 8.0. I ran another test last night to test the FC again and the test water wouldn't even turn pink after adding the powder in and mixing it. I also added some borax (per Pool Math) to get the pH up a bit and it's now right around 7.8.

As a new pool owner, I'm confused as to how I could lose chlorine that quickly in just 3 days. Is this normal, or am I missing something?

Here are my test results from 3 days ago:

FC 8.0
CH - 225
TA - 50
CYA - 40
pH - 6.9

 

[Mr Bruce]

Man, Greenville people showing up like crazy these days. Awesome.

8ppm loss in 3 days is a little high but not outside the realm of possibility. I would bring it up to SLAM level after the sun goes down and do an OCLT. Let us know.

As we get into Jun you will probably not want to go more than 2 days without testing/adding also.

edit: also your pH is low

 

[kimkats]

HI! I have just the thing for you:

Pool School - Basic Pool Care Schedule

A pool is like a pet.........it must be feed and cared for each day. My pool "eats" 2-4 ppm of FC each day depending on weather and bather load.

Kim:cat:

 

[pooldv]

The chlorine level is set based on your CYA level and the Chlorine CYA Chart. Always keep your chlorine level at target for your CYA. Don't let FC level drop below minimum or your pool will be unsanitary and algae will start growing. Test chlorine and PH daily and keep a log until you understand how your pool behaves. The warmer the water the higher the chlorine consumption. Also, more swimmers equals more chlorine consumption. If your pool is in full sun you probably want to increase CYA to 50 to reduce FC loss to the sun.

 

[CPerry25]

The chlorine level is set based on your CYA level and the Chlorine CYA Chart. Always keep your chlorine level at target for your CYA. Don't let FC level drop below minimum or your pool will be unsanitary and algae will start growing. Test chlorine and PH daily and keep a log until you understand how your pool behaves. The warmer the water the higher the chlorine consumption. Also, more swimmers equals more chlorine consumption. If your pool is in full sun you probably want to increase CYA to 50 to reduce FC loss to the sun.

That was going to be my next question actually! Our pool is in full sun all day long and I was wondering if getting CYA up to 50 might be wise for that very reason. I understand that chlorine level needs to correspond to CYA level, so I'll make sure I target based on the chart. Thanks!

 

[pooldv]

Good plan! If you still use more than 3-4 ppm FC as it gets hotter try taking your CYA up to 60. Nice work!