‘Red Pond’ in literary among Goshiki-NumaPonds is not real red. The color of Hell Ponds in Beppu Hot spring (Oita prefecture) reproduces the color more faithfully. Five colors here mean that various colors can be found depending on the weather and season, etc.  Its color is due to the reflection of particles of the melted mineral matter.
To save time, recommend to use a bus for one way. Return to Goshiki-Numa entrance / Urabandai-Kogen by bus (to Inawashiro / Kitakata for each) to pick up the parked car there. Check in advance a time table of bus available per about one hour. In case go forward to the other starting point taking a bus immediately after parking a car.