Your best bet is to see if pedro can hold off on the shipment. Sounds like you need to get your tank under control first. A ray in a 75 gallon that is still cycling is a real bad idea. You could easily see spikes of 2 ppm or higher if a ray is involved. If you can't stop the ray shipment then you will be doing 50% daily water changes to keep the tank somewhat in check which will also prolong the cycling. There is no miracle cycle in a bottle product out there. There are a lot of products that aid in bacterial growth but nothing that is an instant cycle. I would go to your lfs and see if they will sell you some bio media from one of there filters. I have done this in the past to get a tank up and running faster.