FYI the 95g one doesn't fit into the 45g thingy. But it's okay just bought the 95g kit and run it on a different tank. And I'll just buy a 45g refill and continue to use it. Lasts a awhile on a small tank(1 bubble 2 seconds) one 45g carpeted my whole tank with MC. Great because I don't have to for a huge CO2 set up