I start pressurized co2 for my planted tank back in 2010, went cheap for the first regulator and it was dead in a couple days then I built a set myself after browsing Rex grigg, left C, Matt F. and couple more other's build threads.
Turned out there were more option on better parts and rooms for improvement at the time, and I showed my research on what to get and could be done. At the time, with plenty of liquidated industrial/lab grade equipment on ebay due to 2008 market crash and production outsourcing to China, it became a carnival for planted tank hobbyists who want to DIY their own high end co2 system.
In my opinion, the beauty of a planted tank is always dynamic and momentarily, and the hardware of a complete planted tank setup is part of this art, but static and time lasting -- A DIY high end co2 system is also a part of this static art, which hobbyists can appreciate through their own direct effort.
It became another hobby besides planted tank fish keeping. It is fun to build these custom high end co2 systems, but it is more fun to help people DIY their own high end co2 systems and enjoy the accomplishment.
some eye candies, any hobbyist can make their own DIY co2 system such as these:
some fully custom setups in the past: