Being visually challenged I can’t measure what the dimensions are of the pump tubing. A whole head is like forty bones and seems to be wasteful as the cap doesn’t wear. Just the roller assembly, which avast sells for cheap, and the tubing. I found a couple websites that sell precut tubing for the ghl maxi which has the same head as the dos, but shipping is prohibitive. Anyone have a link for either bulk or precut tubing from a source that is reasonable like Amazon or a vendor that has other supplies that I could hit the free shipping mark like BRS, salt water aquarium, marine and reef or similar? Thanks….I did search if it’s been brought up before but I couldn’t find anything.