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.
Also to add, your link shows to me, bits of copper stuck in the pores of the tubing. Every time I have used clear tubing they look like that, and is why I no longer use it.