Planted Tank Obsessed
Join Date: Jan 2008
Location: Sioux Falls, SD
MrJG - It's my understanding that you can use epsom salt (MgSO4) to raise the GH, which you may have around the house and would be cheap if you don't. Wait for confirmation on that though.
honor - TDS stands for Total Dissolved Solids and ppm stands for parts per million. Both are ways of expressing concentrations, just like gallons and liters are different ways of expressing volume. Although TDS can only be used for ions or salts (Mg+, Ca+, etc.). If you've ever taken any chemistry courses, molarity and molality are other ways of expressing concentration that you could potentially interchange with ppm and TDS. If that just confused you more, disregard that statement.