I'm not sure if it's ok or not, but I use mine for both. I wash the siphon tube before and after each use, but that's it. Like I said, it may not be proper, but it's been done.
Clint
As long as you clean it thoroughly there should be a problem. Although keep in mind a 10g will drain very fast with a python giving you less time to spot clean detritus or other build ups when needed. I built my own siphon fron air line tubing and a piece of hard tubing. This was for a 5g nano. That way I could better control where and how I cleaned the tank. Just a thought. HTH
I believe the speed of drainage is based on the pressure at the faucet - so I will use low pressure and just the hose part of the python( think its 3/4?) - how does that sound ?