So I opened up my 370 today for a little cleaning, and was really surprised how almost "rusty" it already looked.
I have been running my loop with distilled water and silver coil, and no aluminum, still it seems the blockīs internals have corroted quite a bit.
I am not sure if it is really corrosion or just residual dirt and pollution from other parts, but it looks damn ugly.
Now I would really appreciate if you guys could help me identify this and present the best option to get rid of it in order to clean the block.
I have already been scrubbing the fins hard with dish soap/water and a toothbrush, but only gained small results.
Is it necessary to be careful when scrubbing the fins, due to sensitiveness?