Ask 'Dr. Spa' Q & A Message Board

Don't your strips come with instructions that interpret the readings? I'm guessing the "Stabilizer" reading is cyanuric acid (CYA). It is part of dichlor. You need it in pools, but not in hot tubs. You want the reading to be low. Actually, when CYA gets too high in your tub, you'll need to change the water. Don't worry about it until the reading gets high. To raise alkalinity, use sodium bicarbonate (baking soda). Your pH up may be bicarb, but it could be carbonate (soda ash) which won't have as much effect on alkalinity.

I'm a little perplexed by your chlorine readings. How big is your tub? How long after application are you taking the readings? With those numbers, hopefully you are testing the next day. If not you may have a problem. You should put in enough chlorine to raise the level to at least 3ppm, calculated or measured 15-30 minutes after application. You should still be able to measure some chlorine 2 hours after. Even in a large tub, a shock dose of 3 tablespoons should result in a 10+ppm reading, and a large residual for several hours, unless you have something growing in there. Read the guides in the pull-down menus at the top of the page, and the Vermonter and Northman routines in the FAQ if you haven't already.