not 100% sure. Alamo aquatics on bandera seem to be pretty nice. and fintique also seems pretty nice. call em up.
or I've got two test kits (one for house one for work) and would be happy to do some basic (pH [usually around 8.0 for SA], Ammonia, nitritr, and nitrate) testing for ya, if you could come to me. just drop it off and i'll tell you what it is on here.