Chlorine evaporates everyday

Hi, I have a vinyl above ground pool. 3,440 gallons
I bought 1 bottle of pool proof and put it in the water and ran the filter for about 8 hours. I added 32 oz of bleach and my pool was perfectly balanced. Although not crystal clear and sparkling like they say on their website. since then I check my water every night and the chlorine is zero. I add 48oz of bleach run the filter for 4 or more hrs. In the morning my levels are fine but an hour after sun hits it the pool is at zero again. I read somewhere that that was okay as long as you add bleach every night and run the filter. For the first two weeks the pool would always recover but now it has a yellowish cast and I'm using up a big bottle of bleach every 2-3 days.
I ordered another bottle of pool proof because I feel like maybe 1 gallon wasn't quite enough the first time and we have been getting a lot of rain.I need help in maintaining my chlorine because my kids swim in the pool everyday and I don't want them to get sick. I'm considering chlorine tablets??? My method of testing is strips because I can't afford the fancy kit. After I put in the bleach at night it does register on the strip, so I know they are working.