I bought one of those and found that the flip-top was not airtight and was made of steel which will quickly rust. I then bought just the lexan container itself which is the same one as the oil res and found that my additive (hyper-lube) reacted with the lexan and caused cracking within a short time.
I have been running straight water in my rig for 3 years now and have had no more cracking problems and luckily no corrosion issues.
My rig.