Tank Upgrade Concern

hI folks!
I don't really consider myself a beginner so to speak, but feel this is a beginner kind of situation. See Ive read, read and reread so many pages on upgrading tanks on this forum and others that my head is starting to spin. And before I really do any damage, I'd like some advice.
Heres the scoop. I have had at least one 15 gallon tank on and off for just over 20 years. Its got a aquaclear 30 filter, and about a dozen grown fish (sward tails and platys) as well as about 15 of their new 2 and 3 week old offspring (will be traded for guppies and other fish as soon as they are big enough). I also have about a dozen shrimp (red cherry type) in the tank. Last weekend, my wife and I decided to upgrade. We didn't really have much of a choice as one of our kids must have hit the edge of my tank and caused a small crack. And well before we have any flooding, we bit the bullet and bought a new tank... a 36 gallon! Now like I said, the 15 is cracked and its just a matter of time before she can't hold it any more. So Sunday we got the 36 home, I set it up. New aquaclear 30 filter, new gravel, new heater, backing, etc. Filled her up and let he sit over night. No issues, so we move forward! I added some cycle, you know the tank starter bacteria stuff the next day (Monday of this week) to start things up. I also added a small amount of flake food to give the bacteria something to eat. Today I added a few more flakes just to be safe. Now heres where I start getting confused. I want to add my old aquaclear 30 to the new tank. I put an extra sponge in my 15 gallon tank filter to get it started, and moved the old filter sponge to the side- still in the 15 gallon tank. I want to transfer the old sponge to the new filter in the new tank so both filters have some sort of bacteria already working. Ive also put 2 cups of new gravel in my old tank to let it get set up. And of coarse all plants (live) and decorations will be transferred to the new tank aswell.
Now that the novel is over here are my questions... When can I transfer my old sponge to my new filter in the new tank without killing the bacteria and do I need to add fish at the same time? I've seen opinions go both ways and want to see what the majority say.
If I transfer all the decorations, plats and filter to the new tank in one shot, is it safe to add the fish and shrimp right away? Again Ive seen many that say my "instant cycle" is sufficient and safe, but I've also read that because the new tank is double the size, the bacteria won't be enough and I should let it do its thing first.
The reason I'm asking all you knowledgeable people is because that crack that's growing bigger by the day has put me into a bit of a time crunch... but at the same time, I don't want to kill all my fish or shrimp. I know ammonia can be very dangerous to the shrimp especially.
also curious what people think of the aquaclear ammonia media. Read a lot about them, and most people say don't bother.
Thoughts on all this??

 

If you move all the things - fish, decor, plants, AND your OLD filter to the new tank all together at the same time, you're golden. Run the old and new filters side by side for a month and then you can take the old one off if you want or just leave it on there
If your tank is cycled, which your 15 certain would be, then there is no reason to remove ammonia because the beneficial bacteria living on all the surfaces in the tank will take care of it for you.
If you are concerned about anything, test test test and up your water change schedule until you are comfortable with the numbers...

 

Just move the old filter to the new tank and transfer all of the fish at the same time. 95% of the good bacteria is in your filter (not a scientific number, but most of it is). You already know that the old filter can handle the bio-load of the current fish you have. And you are more than doubling the amount of water to disperse it in.

Run both filters on the 36 for about a month, and the new filter should be good to go. If you remove the old filter, and decide you want more fish (because who wouldn't with twice the space!) add slowly so your new filter can catch up to the new bio-load.

Edit: Magicpenny75 beat me to it!

 

^ Exactly! You can take literally everything, including all the water, from your old tank and put it into your new one. Then just top up the new tank with fresh pre-treated tap water. This is as close to fool-proof as you can get...and it gets the water out of your old ticking-time-bomb tank immediately.

 

Thank you guys very much!! I had a feeling I was on the right track, like I said, I'm not really a beginner anymore. But there's so much conflicting info that I wanted to be sure before making the swap. So it looks like I'm gonna have a busy evening!!
And yes, my plan was to run both together permanently simply because I will be adding more fish!
Thanks again!!