It isn't the water that does the cycling. It's the critters that produce wasteproducts and the bacteria that break down the ammonia and nitrites that do the job. The thing is, you want to have your tank set up and introduce one fish to get the cycle started. Allow the bacteria to do their thing, without overwhelming them. Buy a test kit to monitor the progress.

petiolaris is right about the pond water not doing anything to help initiate the cycle. However, when you do transfer the fish to the tank the pond water mixed with the conditioned tap water in the tank will help reduce the chance of shock to the fish. Use as much pond water as you can to fill the 75G when you transfer.
For now though, start the 75G full with conditioned (a dechlorinator and detoxifyer like Prime by Seachem that is for city supplied water) tap water. Take as much of the media in your pond filter, preferably the sponge if you have that, and cram it into whatever you are using to filter the 75G. Be careful not to block the flow of water to cause a wet floor. Also, some rocks or underwater decor will be fine. This will help "seed" the new filter with beneficial bacteria. Plants that will fit and survive in the 75G will be a huge asset. If the plants start to die remove them or at least any wilting leaves as this will add to ammonia. Plants use ammonia as food. You can try a fishless cycle by using a free and clear ammonia and the seed material, but don't add plants until it is done if you choos that route. I can give you a link to directions for the fishless cycle if you want. You will need a good test kit for ammonia and nitrite though. If all goes well you can cycle the tank in a few days as long as you have good "seed" material and follow the directions.

Here is a link that might be useful: Fishless cycle

Thanks for providing the Fishless cycle link! I used to do that when I worked for a tropical fish wholesaler, when the sponge filter was getting "ratty". I would simply hook up a new sponge to a tank and allow a few weeks for the "good bacteria" to grow, before replacing the old filter.