Well I used Biozyme to cycle my betta tank, and it was done in a week. Other than that I have no experience with "cycle starters".
Mamie: Instead of paying $60 for a Pyton, I got a little T "inline" valve at PetSmart, and then went to Home Depot and got 25' of clear tubing. I paid $19 instead lol. Also, I would get the Prime water conditioner and use that instead of what you have. As said before, it binds the ammonia and nitrites and makes them not so toxic to your fish. And with that, you would use one capful and just a smidge more to do the 55G. (Each thread inside the cap treats 10G.) If you are using buckets, I space my Prime out between buckets. As in, 10G worth (fill to one thread in cap) in the 5G bucket, dump it in, repeat until you have used enough Prime to treat the whole 55G, (which would be about 5 buckets treated) and then just fill the rest of the tank with water. When I use my siphon, I put the Prime in the tank, (enough for the ENTIRE amount of the water in the tank, i.e 55G worth of Prime) and then start filling it up. I hope this helps you!
Sand: Make sure you don't have any floating around that will get sucked into your filter intake! I made that mistake and had to take apart the whole filter to get all of the sand out....lol. When I put my sand in, I would dump some in a mixing bowl, put it in the sink and run water into it, (but just enough to where it doesn't push all the sand out), and then I got a big mixing spoon and would just kind of stir the sand around until I didn't get any more free floating sand in the bowl, all the while running some water into the bowl. I really hope that makes sense lol. When I do my pwc's, I turn all heaters, filters and bubbles off, and I don't turn them back on until I get it all the way filled back up.
Feel free to ask me any more questions! I was in the same boat as you about 4 weeks ago lol, so I understand how frustrating it can be! Keep doing pwc's every day though, and if I was you, I would do 40%-50% each time until you get that test kit and get the "free floating" sand out.