I think that very little suntan lotion has been washing off from the swimmers. My wife and I usually just go for a swim after getting home from work and we've only had 2 pool parties this summer and I don't think anyone used lotion on those days.
I just use an old j-cloth to wipe the skimmer and I scrub the thermometer with a brush and soapy water. I try to wash out the cloth with laundry detergent afterwards but the residue doesn't come out easily.
My latest pool store chemical report shows the following:
Free Chlorine - 4.5 ppm
Total Chlorine - 4.5 ppm
Combined Chlorine - 0 ppm
pH - 7.4
Adjusted pH - 7.4
Total Alkalinity - 115 ppm
Adjusted Alkalinity - 115 ppm
Stabilizer - 60 ppm (IIRC - measured with reagent and sight glass)
In the spring, I dumped a ship-load of chlorine in the pool to kill the algae. After the water finally became clear, I added granular stabilizer through the skimmer. To prevent algae growth, I've been adding 250 mL of PolyQuat 60 every week, usually the day before shocking the pool with 10L of 12% chlorine.
I've also had to add several 4 kg pails of Alka-Plus and a couple of 8 kg pails of Calcium Chloride. That probably has something to do with the trichlor tablets I've being using for chlorine dosing.
On another
topic about Chlorinator Residue, the gummy residue I've been finding this summer may be a result of stearates possibly being in the trichlor tablets.