Would this problem be connected to my low coolant issue?

So I've been noticing for a little bit that my coolant level would become low. I would fill it and within a few weeks it would be low again. When I checked it tonight the coolant tank was almost empty and I seen a crust like near the alternator. I've taken a few pictures to show what I'm referring to.
The arrows point to where I can at least see it. There's some all the way in the back (top arrow in the picture).
Thanks
2004 Ford Explorer with about 98,300 miles. 4.0 engine.

T is right on. Not sure about other answer, the vehicle only has one cooling system so is leaking coolant, which is a combination of antifreeze and water.
Based on the vehicle age I would just replace any items in that area. If you get aftermarket parts should not cost too much. I'm thinking hoses, clamps, and thermostat, which will have a new gasket.
Make sure to completely clean the surfaces. May take a small screwdriver, window paint razor scraper, and small wire brush.

That stuff is dried antifreeze. Thermostat gasket is leaking and I would be willing to bet that the hose clamp bye the sensor is broken. Seen that many times on that style of engine. Clean then fix those 2 things and use a little water dye and a cheap uv light if you are still going through antifreeze also when you are warming it up check for a pin hole in the hoses because I have seen that as well before you buy the dye and uv light

Very common problem, the plastic thermostat housing is warped and leaking. You'll need a need a new housing installed. It's such a common problem that the housing is made in the aftermarket and cheaper than buying it from Ford. Take this to your local auto parts store and have them order it and take it to a mechanic to install.

Worse than that, the crud seen is caused by leaking water from loose or cracked water hoses and not leaking antifreeze. I would just hate to look inside your radiator. Run and do not walk to a radiator shop.

Looks like a thermostat housing gasket failure to me.