Water Changes When Nitrates consistently read zero?

[Delphinus]

Depends on the size of tank I suppose. I can do a ~6g water change in my 40g in about that amount of time, less if I don't try to OCDishly vaccuum all the rock poo out of all the nooks and crannies. The larger tank takes longer, mostly it's the time it takes to move the requisite water volume through a 5/8" hose 3 times (once to remove from tank, once to put new water in, and once again to empty the rubbermaid with the dirty water into the drain). And that's without trying the siphon the sand.. which I probably should, but I don't, because it's too hard.