canister filter = gravel vac

I had an idea last night about turning one of my eheim canister filters that I dont use into a gravel vac. I usually vac the crushed coral when I do water changes but I only change out 10g of water so I dont get to vacuum as much as I would like. If I turned my canister filter into a vac then I could still only change 10g a week but I feel like I could do a lot more substrate cleaning. What do you think? A possible good idea?
The only thing I would have to make would be the end so I dont suck up the crushed coral.

 

What size tank?

 

My tank is 55g and I have an additional 20g of water in the sump

 

sounds like a good idea to me!

 

that will work, but you could use the gravel vac you have with a filter sock on the end and put it in your sump to

 

Thanks for the return to the sump idea homegrowncorals. I just tried it and it worked great. I just let the cc tumble around inside the vac whereever I put it down until the water was clear then I moved it. It took about 20 min to vac the substrate this way but the water in my tank stayed nice and clear and the water returning to the tank was clear. I think I may be on to something. I also thought about using carbon in another one of my canister filters as a way to really clean up the water, what do you think? Would it help to run carbon in the canister I am using for my vac? Thoughts, ideas, and suggestions always welcome.