No Chlorine Reading

[babybaits]

I'm a total newbie when it comes to pools. I'm trying to get my sons 1839 gallon pool safe for everyone to swim in but I'm having problems getting the chlorine level up. He recently bought this pool and after about a week, he left the filter off and the pool turned green. I've shocked it three times, and by looking at it, the water looks good, but I still can't get a good chlorine level. I'm using HTH 6-way test strips and the most I can get it at is the Minimum level, if I'm lucky. Everything else on the test strip is pretty much at the normal level, it's just the chlorine. I understand that it's being used up faster than I can add it, but what do I do? Do I just keep adding more chlorine, wait, test, and see where I'm at until it's at a good level?

Someone just told me that I need to shock it while I have a chlorine tablet in the pool. I looked it up, and it seems like that might be the answer. Is it?

[Teapot1]

Its a little more complicated than that. Chlorine gets burned up by the sun. To protect the chlorine somewhat you need cyanuric acid (CYA) in the water. You chlorine tablets contain this but it takes time for the right amount (30-50ppm) to build up, could be 10 tablets. In the meantime the sun will burn up the chlorine in around 2.5 hours. So you need to keep adding more to keep everything nice. Adding after sundown will ensure the water is sanitised nicely overnight. Dip strips are near useless for measuring CYA, yes you get a colour change reaction but very unlikely to be anywhere near correct.
You can usually by chlorine stabiliser in a packet to dissolve quicker and get the level up sooner but in general it is a slow dissolving compound.

[Samoa]

Okay so first off I would check how old ur test strips are because yes they do expire and then give false readings, second of all, yes the stabilizer teapot1 talked about is definitely something that helps keep the chlorine from burning off but you mentioned something that struck my mind, the pool is only 2000 gallons so it shouldn’t be that hard to get a chlorine reading let alone get a chlorine reading that is too high super fast due to the small size pool. Personally I would get a test kit (if your strips are outdated and if you do not know how long ago you got them just get some new ones as it’s a cheap way to be sure) that reads free and total chlorine, if possible I would do some homework on what the difference in between them is and how you can have a lot of total chlorine but little to no free chlorine caused by algae etc. i want to ask how much chlorine are you adding into the pool, what type of chlorine, bagged or liquid and is it when the pool pump is running and how are you taking the test strip sample in terms of location in the pool.