The water, at least in parts of Ga and Florida is full of sulfur and iron.
It make for stinky and slimy bacteria in water.
That whitewater hose might as well be clear. The sun on that and you get what you have. A half micron water filter with silver will filter it out and inhibit bacteria growth. Get a 10 in whole house filter. It may clog pretty fast judging by what ours did in South Georgia.
Someone posted a link to filters, recently that had some at a goo price.
I can't find it at the moment.
Until you bury the supply pipe, cover that hose with something.
We use a blue, if color matters, fresh water hose, that is lined, with stainless ends. I think the newer ones are just plated but light won't help bacteria growth. We got our at American Coach store. I think someone said CW had them now.