I just got a 20 gallon tank and would like to put CRB and CRS in it. I was wondering what substrates you guys would reccomend that are avaiable online in the US. My water comes out 7.0 out of the tap. I am trying to stay away from Fluval and ADA aquasoil shipping is about 35 to my house so its more expensive then the actual bag. I do have a old bucket full of floramax i use in my 75 gallon, but i still want to lower my ph. Suggestions!Please help!