Re: Just did my second flush. I think I did some things wrong...
Stones can be many different colours, and the colours tell us what they are made of. Green stones contain a lot of bile and bile salts, which are green. Dark green are older, light green are newer stones. Tan stones contain a lot of cholesterol. Both float. White stones are calcified and if they sink they contain heavy metals like mercery or aluminum. I'm mystified about red stones, but they might be the remnants of liver flukes, which get darker and darker red the longer they've been living in the liver - from blood. Good to get rid of those!
As for colon pain, I've never suffered that symptom. If you mean an acid burning sensation, that's the result of passing toxins from stale and toxin-laden old bile. It's worse the first few flushes and will get less acid-feeling as you do more flushes.
Often people pass "sand" or "sludge", those are cholesterol crystals (if tan) which hadn't formed into stones, and since it's crystaline in shape, it can cut the bilary tubes. It seems that more is released with the first few flushes than later on.
Sounds like you had an awesome flush! Stones the size of walnuts?! Zowie!