Andy Fritz started modifying Russian military rebreathers back in 1997 initially for personal use, but soon enough divers would travel to Thailand to get their rebreathers modernized and themselves trained to use them. Other popular rebreathers had their share of modification as well. The common theme was mechanical O2 addition through needle valves and after around 700 hours of virtually problem free diving the decision to manufacture a rebreather from scratch was made. Mainly because it was difficult to improve the trim and buoyancy characteristics of the many rebreathers modified. One other reason was that exploring a particularly remote site in 90 meters of water called for a closed circuit rebreather that could be expanded with a large capacity scrubber. The final version Pelagian DCCCR prototype was extensively test dived for four months before production started.