Been away for about a month, and now my water tank stinks of eggs.... I have pretty small water tank on my boat (probably about 10l), and after coming back from a trip I've noticed the tank stinks. It really fucking huffs. I've emptied it, and tried refilling it but it really stinks.

I can only assume some bacteria has got in there or something, and over the hot summer has grown. What can I do? I was thinking about putting a load of bleach in there, leaving it for a day then flushing it out with a huge amount of water. Is there any kind of soluble tablet I can put in there?!
