Sodastream Crystal Sparkling Water Maker with Gas Cylinder Megapack 5 "Great!" Miss Davison 30 March 2020 We purchased this in order to cut down on plastic bottle waste. It took a little getting used to, the water must be cold in order for enough carbon dioxide to dissolve in it. I usually fill the carbonating bottles from a water filter jug then put them in the fridge to cool before carbonating. Cooling doesn't take long as the bottles are glass. The carbonating button needs a firm press (both hands for me) until you can hear no more gas can go in. I leave it in for 30 seconds or so before removing. It's really quick and the results are great. And it has cut down on our plastic bottle use.