It took 140 drops and constant swirling to turn the cylinder blue. This is my first test with the TF-100.
I have a 25 year old plaster pool, 20,000 gallons, SWG and sand filter w 3/4 Jandy Stealth. I just re-started a negative edge waterfall feature that runs through a 700 gallon sump by replacing the pump with a 1 HP Northstar . The pool plaster is starting to crumble. I wonder if poor chemistry dissolved the plaster, or the plaster is just dissolving into the water?
I have been shocking with tri recently, and I add acid regularily.
I'll run the CH on the tap water and post that up, too.