I'm new here and recent new pool owner. We moved here 2 summers ago and this is our 3rd summer. our pool is a 16x32 lazy L 22,000 gallon SWG with Hayward pump and sand filter. The salt cell is a generic brand that was replaced by the previous owner in 6/2013 and we moved here in 6/2014. I have been learning and reading about pool maintenance and doing it mostly myself. The first summer we hired out the closing but I did it last year. I opened the po0ll this season and water was clear and did not take much to get all levels in range. I use the LaMotte Color Q Pool 7 Plus and taylor K-1766 salt test kit for testing the water. After opening the pool maintaining the water was about average but noticed the FCL level was slow to rise and on the low side but acceptable. We went on vacation for a week around memorial day. When we came back there was some algae in the pool and FCL was near 0. I shocked the pool and added chlorine to pool and brushed/vacuumed and after a few days it was looking good and all levels in range. Since then it has been hard to maintain the FCL and am thinking the cell is bad or going bad as there is enough salt in the pool.
Fast forward to this week and I noticed the water in the deep in getting a little cloudy so I shocked again 2 nights ago. I woke up yesterday and the whole pool was cloudy like I have never seen. Could not even see the bottom of the shallow end at 3ft. The only way I have been shocking is by using the small pool shock bags from the pool store and not the method I ready about here yesterday. I added 5 of the bags and the FCL level rose and woke up to the milky/cloudy water. I read that the cloudiness can be the chlorine killing off an algae bloom. Is this what is happening. the morning after shocking my FCL was at 4.4. last night is was at 2.1 and this morning it was 1.70. current CYA is 78. This morning the water was clearer and could start to see bottom of shallow end. I added 3 more bags of shock as that was all I had on hand and with in an hour the water was more cloudy and could no longer see the bottom. Should I continue to shock until water is clear or do something different. I have also been brushing and backwashing the filter. Below I have listed my current readings.
FCL yesterday morning 4.2
FCL last night 2.1
FCL this morning 1.7
After adding 3 bags of shock this morning
Salt - 4000ppm
the PH is a little high right now but not sure if that is from shocking and I know CYA could be lower which would require draining and refilling some water. What else should I be doing here. I'm going to call the pool store as they will have me diagnose the salt cell over the phone saving me an $80 service call. I'm almost positive it will need replacing. Where is the best place to get one. They seem to be $200 - $300 cheaper online but have heard of people having problems with warranty down the line. They are nothing to replace but the pool store wants $750 with 1yr warranty and $900 for 3yr warranty and I have seen the Hayward T-15 on Amazon for $460.
What should my next step be. Add more shock or switch to the trouble-free pool SLAM method. It seems most here use regular bleach
Thoughts and help are greatly appreciated.