OP
If you go to 5:25 of the video below you’ll see that there is a good build up of white powder like residue encrusted on the HP Valve Spring and HP Plug of the first stage. More obvious on 11:17, note the gunk and dirt on the LP Chamber. This is actually not so bad, I’ve seen much worse. Water and moisture entering the first stage, even if a little, is never a good thing. This is particularly so if your equipment comes in contact with turbid salt water (less in fresh water - cave).
A wet dust cap that’s reattached to the 1st Stage will cause moisture and vapor to be trapped and make it’s way to the DIN handwheel connector (or Yoke clamp connector). The next time you reattach and pressurize the first stage, the trapped moisture and vapor will be blasted and forced through the first stage Filter and into the High Pressure Chamber and SPG. Then, when you breathe or purge the 2nd stage, the moisture and water will enter the LP Chamber.
After several dives with “just a little water on the dust cap won’t hurt”, the problem will progress. Over time, some or all of issues below will start to form and you may not even know it.
1. The 1st stage filter may get clogged with dirt, salt buildup. Molds may form during long term storage. Work of breathing will be harder due to the dirt build up on the filter. The gas may smell funny.
2. The SPG may get damaged as water/moisture is repeatedly forced into it when you pressurize the system (ie open the tank). The pressure reading will be lagging and not as responsive or get stuck.
3. Gunk and salt will buildup on the HP Chamber and Assembly (Spring, valve, plug, seat). This will cause gas leaks into the LP chamber and the infamous IP Creep (a very bad thing).
4. Gunk and sticky dirt will start to build up and accumulate on the LP Chamber as seen in the video.
5. You could be breathing from a 1st Stage that has molds (fungus) growing inside due to trapped moisture/water. I’ve seen this when servicing some regs that have not been used for several months.
In most cases, the casual diver will not even know that any of these issues exist. But if moisture is allowed to enter the first stage, these issues will happen. Even a 1st Stage that’s lined with gunk and molds internally will still appear to operate normally (think rental regulators). You may think that all is well since your reg is working, but it’s not. Disassemble your first stage, you’ll see the gunk, white powder stuff, green colored stuff and wonder how did it get there. Now you know.
Bottom line is do your best to keep water, dirt and moisture from entering your first stage. Keep the dust cap dry. If you service your regs regularly, these issues will be addressed during the overhaul without you even knowing it.
