So we had an issue with our Rainbow 300 chlorintaor not doing its job. It was old and needed to be replaced, the BB in the elbow was pasted in and not allowing the proper amount of water through. So after that all went well for a few days the FC we kept steady around 2-3ppm then it took a nose dive to barley 1. We cant seem to bring it up and now we have mustard algae we are treating for. I shocked the pool and we vacuumed up the algae on waste and added some Banish.
Now my CH is reading 0 and 2 days prior it was at 280. I am using a Taylor test kit and when i go to add the purple 11 to make it turn red it looks like it is reacting with something because it instantly fizzles and after 5 drops its still clear. I have replaced the chemicals in the bottles and done all i can. I have a feeling it might have something to do with the Banish but it doesnt say anything about affecting CH.