To make these potted ponds, I used a 95 GPH pump (GPH stands for gallons per hour). Although 95 GPH may sound like a lot, it’s one of the smallest sizes on the market and is only appropriate for containers.
Here’s the formula for calculating the volume of your pond or container using imperial measurements: length x width x depth (all in feet) will give you the cubic feet of a rectangular container. Multiply this by 7.5 to obtain the number of U.S. gallons. The galvanized-steel tub used in Tub time measures one foot deep by 11⁄2 feet square: 1 x 1.5 x 1.5 x 7.5 = 16.88 U.S. gallons. To calculate the size of the pump needed, divide the total number of gallons by two, which means you would only need an 8 GPH pump for a container this size.
But that’s just the beginning. The size of the container can also influence the strength of pump required. The longer the tubing from the pump to the water output, the more GPH is needed to keep the water moving. A waterfall entails its own set of calculations, as distance from water pump to water output can be significant. For the best advice and information on selecting a water pump, visit a retailer that specializes in water gardens.
Installing water plants
To install water plants, remove them from the plastic containers they're sold in, wrap the soil and roots in burlap, then place in small mesh baskets (specifically made for water plants and available at most garden centres).
Cover the top with pea gravel (this will keep the soil down). Remember to check the pump's filter periodically, as this is where residual soil will collect.
The smaller the pump, the smaller the filter and the more frequently it needs to be cleaned out.