I am going to order an RODI and people have said they have used the Ebay ones with success. I am limited to the $100 range and have found 2 that I need help deciding between
The first one
http://cgi.ebay.com/Zero-ppm-RO-2-DI-Aquarium-Reverse-Osmosis-Water-Filter_W0QQitemZ110276974873QQcmdZViewItem?hash=item110276974873&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493003312">http://cgi.ebay.com/Zero-ppm-RO-2-DI-Aquarium-Reverse-Osmosis-Water-Filter_W0QQitemZ110276974873QQcmdZViewItem?hash=item110276974873&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493003312</a>
the second
[IMG]http://cgi.ebay.com/Zero-0-ppm-Reef-6st-Reverse-Osmosis-RO-DI-Water-Filters_W0QQitemZ110277956142QQcmdZViewItem?hash=item110277956142&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493523921">http://cgi.ebay.com/Zero-0-ppm-Reef-6st-Reverse-Osmosis-RO-DI-Water-Filters_W0QQitemZ110277956142QQcmdZViewItem?hash=item110277956142&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493523921</a>
The first one
http://cgi.ebay.com/Zero-ppm-RO-2-DI-Aquarium-Reverse-Osmosis-Water-Filter_W0QQitemZ110276974873QQcmdZViewItem?hash=item110276974873&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493003312">http://cgi.ebay.com/Zero-ppm-RO-2-DI-Aquarium-Reverse-Osmosis-Water-Filter_W0QQitemZ110276974873QQcmdZViewItem?hash=item110276974873&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493003312</a>
the second
[IMG]http://cgi.ebay.com/Zero-0-ppm-Reef-6st-Reverse-Osmosis-RO-DI-Water-Filters_W0QQitemZ110277956142QQcmdZViewItem?hash=item110277956142&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493523921">http://cgi.ebay.com/Zero-0-ppm-Reef-6st-Reverse-Osmosis-RO-DI-Water-Filters_W0QQitemZ110277956142QQcmdZViewItem?hash=item110277956142&_trkparms=72%3A570%7C39%3A1%7C66%3A2%7C65%3A12%7C240%3A1318&_trksid=p3286.c0.m14&timeout=1218493523921</a>