The spa is on a separate system than the pool (heater and filter) and the heater is almost always on to keep the temp at 101-104. Since I found TFP, I have been using BBB to maintain the spa but its been a challenge keeping the FC levels up. Before I left for a quick business trip, I put 3" chlorine tablets in a floating chlorinator because I knew the chlorine levels wouldn't hold while I was gone. When I did the FC, CC, TC test tonight with the TFT100, I'm getting very weird results - when I put the R-0003 in, the water immediately turned a dark brown (never happened before). When I put the R-0871 in, the color did not go back to clear. Here's a set of full test results:
FC = 0
CC = ?
TC = ?
PH = 6.8 or lower
TA = color never turned red after a lot of drops. Very light green when I added R-0008.
CYA = 100 (below the 100 line)
CH = 450? The color turned clear and never went to blue
Do I need to just drain it and start over? What is the best method to keep water balanced in a spa that is always hot?