90% I used to buy by the barrel but since I use so little I buy now in batches of 4 kg. 50 kg a year against my 16 kg /year and a pool half yours in size. The roof makes all the difference. Btw, the puppy you gave me is now a very nice 5 years old.
I use my pool about 2-3 times per year. I do zero maintenance and spend zero pesos on it per month and the water stays crystal clear year round. Renting is quite nice.
We use a pool maintenance service (Tropics Pools and Gardens). They come twice a week for 2 to 3 hours and do cleaning, vacuuming, water quality testing, adding of chlorine/algae/ph chemicals, inspection of pump and filter system. Cost is 3200 pesos per month. It's difficult to know exactly what the electric cost is, we do run our pump at least a couple of hours everyday, often all day, and I would guess that it is about 2000 peso per month.