Stripped down my rig today ready for the upgrade and there's some odd discolouration along the edges of my res chambers. The chamber on the right is worse and was the Cpu loop. I opened up the block and that wasn't too bad: A little bit of gunk but not bad considering I've been running the same fluid since April 2015! Would this be caused by bacterial growth or something else, possibly excess heat from the pumps? I had the pumps running with some water round to give them a rinse and they got pretty bloody hot with no airflow on them. They didn't get much air when installed and the Cpu pump would have got the least amount of cooling.