CARE OF POOLS
Miniature pools are easy to scrub in the spring and to keep clean through the summer season. Floating dead leaves or other organic debris that can give off poisonous gas are skimmed off with your hands. Discolored or dying leaves of lilies and other plants can be cut away cleanly. Plants can be thinned out by removing superfluous leaves or pulling out portions of weedy varieties. The pool is kept nearly filled with fresh water—but without adding so much at one time that the water is dangerously chilled.
Permanganate of potash will control slimy, green algae. To one gallon of water add about two teaspoons of permanganate; let it stand until there is little residue at the bottom. For every gallon of water in the pool, add one teaspoon of this saturated solution whenever algae become unsightly. Don’t make the solution too strong. It might kill the fish.
Insects such as the black aphids common on water lilies can be sprayed off with the garden hose to make a juicy meal for the fish. Spraying pool plants with insecticides or fungicides is dangerous unless you use a preparation made specifically for pools, and use it strictly according to package directions.
In winter, most tubs and other containers should probably be lifted and stored indoors. I should think this would lengthen the useful life of small prefabricated pools, too. Small permanent pools should be drained, so ice will not form and crack the construction. This means that the pool must remain empty; either the drain must be kept open or a roof of canvas or boards should be fitted over the top.
FISH AND SCAVENGERS
Goldfish earn their upkeep—a pinch or two of food a week—by gobbling up mosquito larvae the minute they start wriggling. In pools where the mud at the bottom does not freeze, they’ll winter safely out of doors.
Several kinds of snails, tadpoles, and other scavengers offered by specialists consume impurities in the water, including algae. Frogs are just for fun. They’ll often make themselves at home in a pool without any invitation. A grandpappy bullfrog lived in our tiny sinkpool all last summer, retreating to a dark cave between the rocks when the dogs came down for a drink.
It seemed to me the epitome of modern efficiency when I first learned, as a city-dweller, that full-grown frogs could be bought by mail. That purchase made us the most popular family on the block. But we couldn’t offer them comfortable winter quarters in the city; and the last I saw of the frogs, in early fall, they were hopping down the gutter of Fortieth Avenue toward the sewer drain.