"I am going through a real tough time but would just like to say a huge thanks to everyone out there for the support," he posted.
"It ain't about how hard ya hit. It's about how hard you can get it and keep moving forward. How much you can take and keep moving forward. That's how winning is done!
"While being in the water nothing else matters, it doesn't matter what is going on in the outside world as right in that moment of time it is just me and the water and no one can take that feeling away from me."
On Friday it was announced Radford, whose club is Swim Rotorua, will not be nominated for the Rio 10km Open Water event as Swimming New Zealand did not believe there was sufficient evidence he was capable of achieving the published nomination criteria. That was despite an invitation from FINA, the world's ruling body.
Swim Rotorua's chairman Henry Weston said he was shocked and stunned by the news.
He has sent a letter on behalf of the club to Swimming New Zealand chairman Bruce Cotterill.
"We were gutted for Kane. The club is deeply disappointed not to see a nomination for Olympic selection when we feel he has earnt it," he said.
"Kane has been used as a flagship athlete for New Zealand open water swimming in recent years so surely this is a terrible message to be sending out.
"For the national body not to support one of their swimmers it seems very strange."
Swimming New Zealand told the Rotorua Daily Post today there was a "very clear and transparent selection criteria" which athletes must meet and they would not comment any further.
That criteria is the athlete must be capable of achieving a top 16 placing at the Games with the potential to win an Olympic Diploma (top eight placing).
However this will be one of the main factors Radford will refute if he does lodge an official appeal.
Initial contact was made by Auckland barrister John Munro, who is representing Radford, to Swimming New Zealand yesterday.
Munro said he believed Radford had "good grounds to appeal".
Weston agrees with this in his letter as well as raising concern about what message New Zealand's decision sends out to clubs and regions across the country.
"The question for you is why a national swimming body would ever choose not to support one of their swimmers in this situation.
"Like Swim Rotorua, we would expect you to be proud of, and celebrate, Kane's achievements and to support him to perform in the Olympic environment.
"That you have chosen not to - when you could equally have chosen to back him - will speak volumes to swimmers across the country, and particularly to those aspiring open water athletes."
Weston said the local swimming community would back Radford and an appeal - if it was to go ahead - especially as Radford had always supported Swim Rotorua.
In 2012 the club suffered a difficult year as they were coach-less with many athletes "wavering en masse" and despite Radford having just received news of failing to make the 2012 London Olympics in similar circumstances to now, he made a special visit to the club.
"Kane made the effort to come down and talk to our athletes about battling through hard times and providing them with inspiration to continue," Weston said.
"It was incredible considering the day before Kane had heard the most disappointing news of his career.
"To do what he did, with the results he achieved with our athletes, was just an incredible act of selflessness."
