Hi TFP! I am having trouble retaining chlorine in my salt water pool.
I bought the house a week ago, and tested the water for the first time to find 0 FC. I spoke with the previous owner and at his advice added bleach to raise FC to shock level of 20 (CYA is 50). The next day, it looked better but cloudy in the deep end, and FC was about 10. Three days later (today) FC is back to 0. The water looks pretty clear but there a brownish yellow sediment on the sides and floor of the pool. The polaris vac cleans it up (or maybe just stirs it around) and it brushes off easily. I have no idea if this is pollen/dirt or algae. I went ahead and added more bleach today to bring FC up to 20 again.
I've read on this site and everywhere I can...I need to determine why FC keeps falling to 0. These are my theories:
1. Is there algae in the pool that keeps returning despite the shock level of FC? Wouldn't the SWG maintain at least some FC after the shock kills the algae? Could this be the dreaded mustard algae I've heard about? I know you recommend shocking and holding the level in your SLAM guidance (but you'll have to refer to my biggest problem at the end of this post...)
2. Is the SWG failing? The right lights are on, and it isn't giving me any alerts. However, I tried testing FC using water right out of the return, and it read 0 FC there too. Not sure if this is an accurate measure of SWG performance or not. Do I need to turn up the output percentage? I've had it about 40% with the pump running 12 hrs/day. Although I'm trying to leave the pump on 24 hrs at a time while adding all the bleach.
3. Could phosphates be to blame? I've read that high level of phosphates can cause a SWG to perform poorly. I've also read here that most of you consider phosphates not to be an issue. I had a pool store test the water just for comparison (don't stop reading), and their phosphate test showed 1200 ppb. I added 12 oz of seaklear phosphate remover today.
4. Could this be a result of CYA being too low? I know 50 is a bit low for SWG pools. The pool store test actually showed CYA of 10, but the members of TFP have said not to rely on that. If it really is 50, is that low enough to cause this big of a problem? The reading of 50 came from the TF-100 I got from the pool's previous owner.
Ok here is my biggest problem. I do not live at the house yet, and I'm currently an hour away. It isn't practical or possible for me to go check the pool every single day while I'm trying to fix this. Should I just put it on hold and start a massive attack in a month when we move in? Or is there a way to handle this with a once/twice a week visit? I'm going crazy over this! Ready to get a big excavator and smash up the whole thing!