But your 10% water changes weren't with a fresh batch of saltwater. You simply swapped water from another existing tank if I remember correctly. When I say your methods, I mean the methods you have been advocating. Whether you invented them or not is off my point. They are methods that, as I am sure at this point you have seen, are considered unconventional and out of date by many.
You admit that your results were unsuccesful. I appreciate that concession. You have come across rather firm in your beliefs of the proper methods to use.
My suggestion here is simply to try out some of the newer methods, that were developed based on trial and error, quite possibly stemming from the methods you used in the 70's, and just recently. I am sure that others too met with a lack of success using these, and developed them further based on that.
The choice is, of course, yours. I am merely offering a suggestion.