Just some information as a RB instructor - the Atlantis/Dolphin was/is a entry-level rebreather from a decade ago. That being said it is an older design which really doesn't save the diver much in the way of total weight, added bottom time, or swimming efficacy vs. a simple set of doubles.
A simple search on Rebreather World should reveal threads about folks migrating from the Dolphin to CCR, or MCCR. The Sport Kiss is an almost ideal and cost competitive entry-level MCCR (mechanical closed circuit rebreather) that is smaller than the Dolphin, increased bottom time as you have full control over your PO2 and doesn't gurgle bubbles like SCR's. That being said, if your peruse Ebay you can often find divers unloading their Dolphin SCR's quite regularly.
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