For About Three Months I've Observed Normal Appearing Stools Leech

For about three months I've observed normal appearing stools leech bright red blood. It only takes about 30 minutes or less to become visible and the longer I don't flush the deeper the red becomes. I discovered this quite by chance when I forgot to flush one day. Twice now, I've had my GP check for blood in my stool and he tells me the results are neg. I finally took photos of several stools, over several weeks and with only one exception, all eventually leech blood. I should mention this blood does not mix with the water, nor do the stools begin to change color, nor do they turn the water brown. Only when I flush does the water churn up brownish/red. I've finally concluded only photos over a 2 week period will convince anyone. age 63, wt 125 5'6" BP 120/60, Brief but incomplete history 3 small aneurysms (illiacs and Abdom) -ulcerative colitis, ischemic colitis, ulcers, Ehlers-Danlos Syndrome