Green stuff will grow in one of those translucent thin white hoses even if water is always moving. The algae etc latches onto the plastic and the sun and whatever might be in the water feeds it.
A lined hose preferably one with silver in the lining designated for drinking water is perhaps the best equipment...with stainless steel ends or at least solid not plated tin fittings.
Not sure if it is still available but you could buy any length then they shrunk it to minimum fifty feet with ends of course. Wasn't cheap.
Then we had the lined blue hoses, which is what we ended up with , with stainless fittings. The copies we now find are hard to flex and have aluminum ends that are perhaps no better than the plated sheet tins.
A lot of bleach will deteriorate the inside of the hose particularily rubber hoses if you still have one.
People who sit in one spot all season will cover their hoses with either with split pvc pipe sections, which should preferable be darker than that maybe the gray pipe or cover it from the sun someway. Birds will peck holes sometimes in the thin cheap hoses, who may rupture or spit the fittings off too as well as thing sewer hoses.
I really don't know a good way to dry the inside of a hose unless you have plenty of time perhaps a funnel and strong fan. :)
Water sitting in them is breeding ground for algae and other things anywhere.