Cool! The system works great for me, I hope you'll have the same success
I've never timed it properly, but I can say that it's far far quicker than buckets and bottles I used to use. It probably takes me somewhere around 40 minutes to do a 70% water change on my 280L. Only five to ten minutes of that is actual hands on work though. I only need to keep an eye on things.
Probably takes 10-20 minutes for the 105L.
For me, the flow of water being drained or pumped back into the tank is the same as a tap turned fully on. It's fast but it's still slowish if you're changing 200L of water