HYDRO-PRO is our line of compact expansion tanks for sanitary hot water with a fixed potable water butyl membrane and internal epoxy coating. These tanks are made of carbon steel and MIG welding that eliminates any sharp cutting edges inside the tank. The shape of the membrane is designed to avoid any water stagnation and therefore the growth of any bacteria. These tanks are used with boilers, pumps and as anti-water hammer. The sizes range from 5 to 600 liters (1 to 132 UK gallons). They are certified according to PED 97/23 CE, WRAS, ACS, IAPMO and NSF.