When using pipe-work in connection with the pond it is important to use the right sort for the job. Many stone ornaments use copper, or lead pipes in them, but these shouldn’t really be used in pools, especially small ones as both metals are poisonous. Rubber, or plastic pipes should always be used for any lengthy runs. As rubber perishes in time plastic is usually the preferred material. With 1/2 or 3/4 inch pipes they do not need to be reinforced, but for 1 inch, or 1 1/2 inch the pipe will kink very easily round corners unless it is reinforced and sometimes rigid pipes are used as an alternative because of this.
Most modern pumps will accommodate a variety of sizes of hosepipe with 1/2, 3/4 and 1 inch being the most common. Usually stone fountains use 1/2 inch pipe although some use 3/8 inch both of which will fit onto the fountain adapter of most pumps. Where a larger flow is required such as for a filter or a waterfall ¾, or 1 inch should be used.
For a very large flow such as for a stream effect then 1 1/2 inch should be used in conjunction with a very large pump.
Again where pipe-work is attached to the inlet of the pump to suck water up out of the pool a large pipe should always be used so as to allow the best flow into the pump. Rigid pipes are seldom used except in connection with filters. Here they are often used to return water back to the pool. A large pipe is needed because the water is usually not under any pressure and travels along the pipe under the influence of gravity only.
All plastic pipes should be bought from reputable dealers, because the plastic should be of 'Food Quality' so that it has no extractable cyanide compounds in it as do some of the cheaper garden hose-pipes.