Before putting anything in the aquarium, make sure that the glass is quite clean. You will not have the opportunity again for a long, long time. If you have an old tank, scrape off all lime deposits from the glass. Scrub inside with ordinary table salt and a very little water. Rinse well. If this does not remove all deposits, use steel wool or a razor blade scraper.



Throughout the United States and Canada, dealers carry packaged sand for aquariums. This is the recommended sand, but if you are in a position where no dealer is available, we suggest you use river sand or one of the coarse heavy sands used by builders. Silver sand and other very fine kinds are of no use because they rise too easily in the water. Because much of the sand throughout the United States is lime bearing, a simple test should be made to see that your sand is free of all lime.

Heavy sand ballast of several kinds, having different colors, can sometimes be obtained from any builder's yard. It must be put through a wire sieve to remove all stones, and then washed thoroughly to remove all dust, dirt and finer sand.

The washing can be done by placing it in a bucket and under a tap in the sink or a hose in the garden. Stir thoroughly until the water overflowing from the bucket runs clear. A test can be made by putting some of the sand in a jar and pouring water on it. If the water is not clouded, the sand is ready.

Now the sand, still wet, is spread carefully over the whole base of the tank. If you are using the biological filtration method of keeping your aquarium clean, hold the filter panel firmly in place with one hand. Then take handfuls of sand and throw lightly on filter and around edges to cover filter. Add more wet sand to whatever depth you may wish. One to two inches is good. Generally, it is sloped to be deeper at the back.

At this point the rocks can be added. If more than one level is needed, two or three fairly large pieces of rock can be placed in a row, or a semicircle, and the place enclosed by them filled with sand. If just one level is planned, smaller pieces can be placed at desired spots as though carried there by river action.

Do not overdo the rockwork. We have seen tanks that look more like a stonemason's yard, or a cemetery, than an underwater scene. Remember that rocks displace water, and that of the two, water is the more valuable to the fishes and plants.

The best kinds of rock to use are the sandstones, of which there are many kinds, in various shades of brown, yellow, green, and gray. Granites may also be used, and some varieties of quartz, which give a very fanciful effect, but are inclined to present sharp edges on which fish may injure themselves.

When possible, the stone selected should already be water-worn, as this looks more natural and is not so likely to be injurious as that newly broken. Limestone is not safe to use as some kinds allow the water to dissolve the lime and so harden the water. Marble, alabaster, spar, and gypsum are the worst offenders and should never be used. Colorful rocks should be tested before using, as some of them contain chemicals that are poisonous to fish; for example, copper-bearing rocks. Slate, coal or coke (first well washed) can be used with effect at times.

When all is ready, we can turn our attention to filling the tank with water.

Congratulations! You are on your way to having a fully functional aquarium.