I hate to promote a specific brand but the tubing on the Python is so much nicer than the cheapie Petco vac I used for a bit on a previous tank -- way easier to crimp and release with one hand. (This may or may not apply to the one you're using)It's a big thick tubing that does the gravel vac I got it from Petco 2 years ago for my freshwater tanks but yea the piece I do water change with it's like easily a 2-3 inch diameter opening it's big
*aside -- not sure this is the case but a 2-3" diameter tube might be bigger than you'd want for the exposed sand areas I'm guessing you have to work with (...but just speculating based on the one pic you posted)



