Is it possible to buy just an Atomic Aquatics T3 first stage?

[buddhasummer]

You'll notice zero difference between using an Atomic over a MK17. I'd imagine the Atomic is better balanced than the MK17, wouldn't be hard, but even then if using a balanced second stage is likely unnoticeable.

Personally I'd stick with the MK17 and be happy or if you're itching to spend money buy an Apeks FSR, better balancing than a MK17, better port positioning (IMO for single tank BM) super simple, easier to get service kits for too. I'm a diaphragm guy in the interest of transparency.

 

[BoltSnap]

I have lots of Atomic and SP regulators in addition to other brands. Atomic is top best breather, the auto venturi adjustment is excellent. SP comes close second. Other brands (Mares, Cressi and AL) are being phased out.

Atomic regulators with sealed first stages are the most reliable regulator out there and you can go for 3 - 5 years between servicing without any issues (none that I have seen over the last 20+ years of using Atomic regulators). I use an ST1 as my primary regulator but I have Tx, B2 (had is since 98' as a B1 that was upgraded to a B2), M1 and Z2 sealed. They all perform the same when all tuned to the factory specs but they differ in the material they are made of in both first and second stages. The M1 and Z2 are best value since they don't have the grossly overpriced proprietary second stage hose swivel (The Z2 doesn't have a first stage swivel turret). If I had to do it all over again, I'd just have the M1 for personal use and the Z2's for the dive school training equipment fleet and nothing else.

As for taking care of the Atomic regulators, I rinse and soak them but leave the LP second stage hose high up while the two stages immersed in water. No issue with this method at all. I just had my heavily used ST1 serviced for the first time since 2012 and no signs of water intrusion or any type of corrosion or contamination on the used filter or the other replaced internal parts.