Upgrading 10 gallon to 20 long. Need advice please.
So I've decided I'm going to go buy a 20 gallon long and move my residents of the 10 gallon to a bigger home.
Currently, I have a substrate of flourite black sand. I plan on moving this over to the tank, but I don't think I'll be buying more to add to it. I want to add some eco-complete instead. I have that in another tank and it's just so much easier to plant in and clean, it looks better to a some extent, too. I'm going to try and keep one half of the tank as sand and the other eco complete, since I have pygmy cories who prefer to have sand.
The 10 gallon has two filters on it at the moment, a double sponge and an aquaclear 20. I'd like to drain the tank, put my fish in a bucket and set up the other tank with the current filters/plants/substrate + the new stuff. I don't have anywhere else to keep these fish and don't have enough room to keep both tanks running. I will be pouring the old tank water in the new tank as well (even though that doesn't matter much for bacteria, I know). I just figure the two filters, one being a well seeded double sponge that's been running for months, would prevent the 20 gallon from needing to cycle. The aquaclear has been running almost as long as the sponge filter.
Is there anything I should do or be cautious of? Should I treat with prime and expect ammonia spikes? Am I missing anything? Thank you.