Hey J and Welcome. You probably already know that we need reliable results to give reliable answers. You being in Canada greatly complicates you getting your hands on a reliable test kit so for now we all just may have to guess.
When there are questions if there are any undesirables in the pool, The
Overnight Chlorine Loss Test Is the answer, but you need your own testing ability to perform it.
inspect your cell for scaling. The inside plates should be shiny with no buildup. If you see any, knock off what you can with a popsicle stick and rinse what you can off with a hose. Soak what’s left in a 50/50 MA bath. It will fizz and you stop once the fizzing does.
You also need to know your CYA level to keep yourself in range based on the
FC/CYA Levels. If the CYA is too low the sun can burn off your FC in 30 minutes.