Last few batches I've made with water direct from my solar hot water because it comes out at around 65 so I use less gas to heat to mash temp. I've just suddenly thought to myself, is this a good idea? A quick Google produces information that hot water heaters produce nitrate which is linked to oxidation and stomach cancer. Also metcury, lead, all the good stuff. Great.. just mashing my latest pilsner in it.. I do have an esky to catch the overflow relief valve when it gets too hot and the sides are stained a light blue from the water. It used to run into our new tiles and they're stained white What are your thoughts on this?