I do grow tomatos. To be honest all you need is one of those long grow bags and some sun and you get great results with just that. If someone told me that they wanted guano for tomatos, I would laugh. "I get ya, ".

pH testing and altering stuff - I use this for my aquarium. Genuine answer.
ferts - probably a good idea to just get what you want in smallish quantities, but from a discreet source. And pay cash.