the stock tubing is very loose on the fittings, so it should easily come off. Since you are going to a smaller tubing anyways, why not get 3/8" tubing, heat and stretch the tubing, and have no need for any clamps at all.
As far as cleaning the loop, I don't know that I would go to bleach, maybe vinegar and baking soda, but I think bleach is a little harsh, and if you leave some residue, I have no idea how it will effect the tubing if pumped through it.
The pump is fine for that loop, but not as powerful as say a 655/35x that may blow those hoses off the fittings (and why I mentioned it not being so powerful).
If the rad is green, it was either a chemical reaction to the copper (oxidation) or you had natural light shining on something to grow algae. They do make additives to keep this from happening in the future too.