Bests & Worsts Reviews from Amazon

I was buying 3-4 cases of sparkling water a month. I thought Sodastream saw a good idea at first. However..... The replacement tanks are pricey, but still were saving me about 40-50% over the bottles. Not a great savings, but okay. But the real problem is this. My Sodastream kit came with 3 bottles. After 5 months of use I am finding that the bottles don't hold the pressure very long. I assume the rubber gasket in the caps were wearing out, so I have tried over-tightening. This does not seem to work. I will use up the 3 tanks I have, and switch back to buying bottled sparking water.