In a bit of good timing, just as my current 10 gal tank has developed a slow leak, my friend offered me his empty 40 gal octagon tank. I currently only have 1 Cory catfish in my 10, but I’d like to get him swapped over ASAP. I’d also like to use sand substrate instead of gravel, as I plan to get some more Coreys once settled. I’m hoping to get some advice on swapping over. I guess it’s basically a fish-in cycle?. I’ll have new pumps and filters for the tank, but I plan to hang the old filter and some gravel in a bag on the new tank. Should I use most of the water from my 10 and then top off the rest with fresh treated water, or use all new water? Should I add some bottled bacteria (Seachem stability, etc .)to help with the larger volume of water? I want to do this right, but as I said, my old tank is leaking and I don’t have a ton of time on my side. All advice is appreciated. Thanks!