If you scroll down the above ^ provided R2R link, they have steps to save the link to the ARC website, as an icon on your desktop.
Just substitute atlantareefclub.org for the R2R address in the directions, then save it to your desktop as the directions say..
Once you have the new icon, click on it and log in as you normally would.
Otherwise, you can open your browser (Safari on an iOS device) and search for 'Atlanta Reef Club' as you normally would. Then log in.