Justin,
The single best investment you can make in this hobby IMHO is an RO/DI filter. I tried not getting one and had nothing but problems for years. Your tank can only ever be as good as the water you are putting in it. Different jurisdictions have very different tap water, just because your friend's water is OK does not mean that yours is. My tank is doing 10x better since I went to RO/DI water.
Good Luck,
James