Make your own SOG for a few quid, easy and cheap and works. Thread on here somewhereAt the thick end of a £100 it's far more expensive than fluid. I use Thetford fluid and when bought on offer it's £14 for 4 litres which last us about 12 months. Unless I were to switch the sog each time I change M/H based on 3 years ownership fluid £43 sog £95, net loss of £50. It's a no brainer for me. But then I'm just tight.