We have a 6' diameter inflatable pool. It holds about 18" of water, about
300 gallons. If you only use chlorine bleach, you will still get algae in a week,
in the summer in SoCal. But if you add a teaspoon of "Zep" brand "root-kill"
you can maintain the water at least a month in full sunlight. This is
copper sulphate, which when I was a kid my dad used to reduce the filamentous
algae that grew in our bass pond.

Beautiful blue. Also a fun reagant, mix with baking soda to make a nice
pigment. Mix with egg white and it lasts a long time, esp. on porous concrete.

I've also got a little $10 pump moving the water through a 1 pint
water bottle filled with former pillow stuffing. The fibers trap algae
and the other particles you'll otherwise observe, keeping the water
clear and nominally clean.

Happiness is sitting in your underwear, beer in hand, in your $30 inflatable
backyard pool in Irvine. Under the shade of a backyard umbrella, as the
world heats up around you.

A lot less hassle than a pool or jacuzzi, and all the privacy you want.