We have three ranges of above ground tanks for rainwater use; standard plastic tanks (polyethylene), one-piece insulated GRP tanks, and sectional insulated GRP tanks.
Standard polyethylene tanks are very popular and are available in a wide range of sizes. They are lightweight, robust and very cost-effective. However, if you want the tank to be insulated, then this is something you have to arrange yourself. If the tank is used only for garden irrigation, then we recommend it is drained at the end of the growing season, and the pump removed for the duration of the winter months.
GRP tanks are more expensive, but have the added advantage that they can be supplied pre-insulated, which can be a useful benefit in some situations. One-piece tanks are available up to 9000 litres capacity. For greater volumes or where access does not permit a one-piece unit, then a sectional tank can be used.