Welcome to TFP! :-D
17 bucks a month is what it costs me in chemicals (mostly chlorine and a small amount of acid) for my 16,000 gallon pool (shown here and here) used every day for 1-2 hours (longer on weekends), but I have a mostly opaque pool safety cover and a relatively low 1 ppm FC per day chlorine usage because of that. Your costs will depend on the size of your pool, how much your pool is exposed to sunlight, the bather load in your pool, and the cost of chlorinating liquid or bleach in your area. Most pools use closer to 1.5 to 2.5 ppm FC per day, though this varies considerably. My pool operating costs are dominated by my pump electricity costs since I have solar heating, we keep our pool warm at 88F, and my marginal electricity rates are around 32 cents per kilowatt-hour so this averages around $90 per month during the swim season (not counting gas assist at the tails of the season). Those electricity costs are half of what they used to be when I had a single-speed pump -- I now have an Intelliflo variable flow pump.
Richard
