Oh for sure - your feedback is totally helpful, I agree the colors are not obvious (especially red being good), perhaps my tone sounded dismissive but that was not the intention at all - symtom of a quick response from my phone! I'll definitely work on improving the readability of the colors and what it means (tricky to find the balance between nerdily over explaining how it works)
the color allocation is closer to chinese symbolism than western. You don't need to change it, just describe it somewhere, probably with a rainbow strip, maybe bottom right, like a scale symbol on a map.
If there was a key explaining what the colors meant that would be great. And maybe the option to select colors or pick between a couple of alternatives - i think in western culture green is good but in Chinese i think they normally think of red as the best - just being able to swap between those two defaults would probably be enough - thanks for your hard work - much appreciated