It indeed bubbled. What do I do about it?Pour some muriatic acid on it and see if it bubbles.
If it bubbles it is calcium and probably from your plaster.
I just bought the house last fall but I have the pool plans from when it was constructed in 2001. I don't know if/when it was replastered sinceHow old is your plaster?
According to the plans, guniteWhat type of finish is it?
Oh I don't know then. How can I find out?Gunite is the concrete shell. Then there are many different types of plaster finishes from different manufacturers that waterproof the shell.
pH was ~7.6 a few weeks ago. I've since raised the FC to 12 which makes the pH test inaccurate to my understanding?What is your water chemistry and CSI from your TF-100 test kit?
Temp is about 50 since it's still chilly here. According to poolmath my CSI is -0.98What is your water temperature?
CSI below -0.6 can cause etching of the plaster. If you play what if with Pool Math and see how your CSI increases with adding calcium you will get and idea of where to raise the CH to get your CSI into -0.3 or above. CSI will also rise as your water temperature rises.According to poolmath my CSI is -0.98