We finished and filled our pool in mid October 2011 and haven't been doing much except maintaining the pH and chlorine. It seems almost to be too simple. I have been adding acid about every three days to keep the pH down and it seems like no matter how much chlorine I add, it hardly even shows anything on the test. How important is chlorine in the winter? I don't want to waste money on something that isn't needed. We have used the spa 3 times since we filled it and the pool once for about 20 minutes. Right now the water temps are about 45 degrees so I wasn't even sure if I would need chlorine since it is so cold. Once the water warms back up above 50 deg I am going to add salt and get the chlorine generator going, but for now we have just been adding liquid chlorine.

Hmm....I started up my new pool 3 weeks ago....initial temp was 60 degrees, within a week it fell to 50 degrees due to winter weather before the solar, cover, and heat pump got installed. Regardless, I noticed CC's rising within just 2 days and even with 1 FC in the pool...essentially, even if you don't see it, if you have a good test kit that checks for CC and CC is above 0.5...than you're already behind the ballgame and algae is forming. You don't want to let it get established. On the other hand, if your water temp is staying under 50....maybe you'll be lucky...but I'd still monitor the CC value daily and if it is anything but zero, start to put chlorine in....although avoid shocking for whatever number of days your pool builder suggests (likely 10-14?) as shock can raise ph.

I am 3 months in and should be able to shock it but haven't have a need to yet. Only when it is windy does anything ever get in the pool but since I live in a desert it is only a few small leaves. My CC has always been at 0

What is your CYA level? For now I would raise it to 40 if it is below this. If your CYA is low the sun will still burn off the chlorine even though it is cold. If you do have CYA and you are not holding chlorine then you probably have nascent algae and will need to follow the advice on how to shock your pool in pool school. Once your pool temp is up, you will definitely want your CYA to be around 80 in Vegas.