We don't get involved in water treatment for aquariums and ponds but we get asked about it quite a lot. Where we differ is that the fish keeping industry, regardless of people take it very seriously, doesn't have any kind of legislation connected to it. Most of the time our UV equipment is used on systems with the purpose of treating drinking water. That means there are some big differences in what we do. For example, you will often see UV systems for ponds made out of plastic. Because UV can cause leeching of questionably carcinogenic by-products in plastics, you will find the type of units we sell are only made of stainless steel (304 or 316). Stainless systems are much more expensive mainly due the manufacturing process rather than the raw material cost, but they make an undeniably safer system (as is often proven with the industry standard WRAS approval). For UV systems to use in ponds and aquariums, your best bet is to head to your local aquarium supplier. They'll probably have a couple to choose from.