Currents/Water movement

Can I ask for some advice on my setup?
I'm a newby to the Axolotl hobby, I am in the process of cycling/setting up my first tank.
My tank is 75 gal capacity, the canister filter I will be using is a SunSun 302b unit that has a 264GPH pump duty.
I added filter media from one of my other filters to speed up cycling and have been doing water changes using water from a mature tank for the last 6 days, but am still getting 6ppm Ammonia.
Today I added one of my larger 304b filters from my big tank to see if I can hurry the cycling along a bit, this filter has a pump duty of 525 GPH.
So I now have about 789GPH on my little 75 gal tank.
Is this amount of water movement going to stress the Axolotles when I introduce them?? There does not seem to be much actual water movement/currents visible to me. When I feed the goldfish I have in there with flakes they don't move about too much with just the small filter running. There is some visible current with both filters running, but I have the larger filter set up with just a straight inlet, no spray bar.
I attached some videos of the issue, what do you think? Not sure if the links will work or not!
Hoping the tank will cycle in the next few days with the extra filter to speed it up a bit, as soon as the ammonia levels drop I'll remove the big filter.
https://drive.google.com/open?id=15WBSlyWv1CHGWD51lvUbzDPQsFU3_cEV
https://drive.google.com/open?id=1pNL0ui6qDcZBAeS0UNxym-dIzTtjSFeE
TIA chaps

Hi there! I dont honestly know how much is too much, flow wise, but will share what I can to help, for lack of any other replies!

So I have read that if the plants move, the flow is too much. Here is a link that seems to provide some useful hacks to slow down the flow:
https://www.aquariacentral.com/forums/threads/sunsun-flow-rate-adjustment.265789/

Now in regards to increasing you BB (beneficial bacteria), using water from one tank in water changes to the other actually does very little to increase this. The reason for that is that the BBs live in the substrate, decorations, and especially the filter of the tank, not so much with the free-floating in the water. I would suggest stealing some decorations from the other thank, or substrate (keeping it in an easy-to-remove, hard-to-swallow mesh bag), while making sure you jar the decoration\substrate during the move to keep as much of the bacteria attached as possible. Another thing you can do is purchase Seachem's Stability, which contains bacteria spores who will settle into their new home in roughly 24 hours as live bacteria.

Hope that helps some!! Good luck!