My understanding is that the Champion tank is step down in some features from the Well X Troll which has some extra premium features Amtrol has built in over the years. I assume the price for Champion will be less. On the Amtrol website they list a Value-Well tank series that might even have a lower price. I am in the process of checking From the pictures on the Amtrol website it looks like the Champion still retains the Well X Troll's basic premium construction (the internal hoop to anchor the diaphragm and the drawn steel tank construction which keeps the tank lightweight and easy to carry down stairs and maneuver into cramped pump house positions. Talking to the Amtrol Technical service they indicate the Well X Troll has a Stainless Steel under-tank connection elbow which gives the tank a few more years life when connected to cooper Plumbing, (the Champion line has a malleable iron connection elbow) the Well X Troll has a 100% Butyl rubber diaphragm (the Champion has a Butyl/EDPM rubber blend diaphragm), the Well X Troll has its plastic liner made of virgin (new) plastic (the Champion's plastic liner is made of a blend of new and regrind plastic). The Amtrol website has their phone number that I called to get that information -- they could possibly elaborate further on differences for you.
The new Smart Controls show the water temp instead of ON. I just had to replace a Smart Control on my Amtrol Classic Boiler and the Amtrol tech told me that the temp will be displayed and not to be alarmed.
Amtrol first became popular with their well tanks. In addition to their well tanks, they offer plumbing and heating, refrigerant and chemical cylinders, and also deal with both commercial and industrial products.
AMTROL-the makers of Well-X-Trol.
Your WX-203 has gone bad and your gauge is stuck on 40lbs. Get a new gauge and tank before you burn up your pump motor. I don't see how your water could go from hard to soft. It's going to be one or the other.