Hi - I've never seen water ozonation referring to mg/hr. I do have an ozone air purifier as well as a medical grade ozone machine, but this doesn't ring a bell. You may try asking on the yahoo board with that dr. Saul Pressman. (Please keep in mind that he is not a dr. of any traditional medical licensing, and he does sell his own products).
Also here is a link to a yahoo group run by Peter Jovan. He helped me a great deal and I got a lot of what seemed like very reliable and good advice from him on ozone. I'll give you the link. Perhaps he can take a look at the machines you showed me - I've never heard of those brands and couldn't advise you. They seem inexpensive enough to take a gamble on, but I'm sure you want to get what will work well. Here's Pete's group: