Any good pet/aquarium stores in Hilo?

[ohanamama]

I've been looking to turn my 150g freshwater fish tank into a saltwater tank, problem is I can't find supplies. Walmart didn't even have enough gravel to re-start my freshwater tank - only 2 medium bags! (Guess I should have shipped that too!!) I tried Staceys today, same story. They did have some sand, but only a few small bags - not nearly enough, and only 20g powerheads. Has anyone ever used sand/rock from the beaches? Altho I would feel too guilty to take any sand from the east side of the island!!
Sooo where's a good place to go?