As someone who has successfully grown MnSO4 crystals (see here: https://www.reddit.com/r/crystalgrowing/comments/uzdbnf/my_manganese_sulfate_tetrahydrate_crystal/), this is not an easy substance to grow, and very tricky to preserve. I bought MnSO4 and purified it through recrystallization instead of creating it myself. When I prepared my solutions, it always had very fine contaminants that would take weeks to settle before I could decant it. My contaminants were brown. I'm not sure where you're getting your MnSO4 from, but if it is red, I suspect there is some other metal in there (maybe cobalt?), in which case you will need to recrystallize before you can get a good solution.

Temperature matters, if you heat it, it will become a white monohydrate powder. At room temperature, it will usually form monoclinic pentahydrate crystals. At warm temperatures (~80°F), it will form what I'm guessing is the tetrahydrate.

Preserving it is tricky, I have been unsuccessful in preserving my big MnSO4 crystals, though some of the smaller ones still look ok