I find 2tblsp per gal works good for me. If you've noticed good results with 1tblsp then I guess we could acuratly say 1-2 tblsp per gal. I did 3 tblsp once and didn't notice anything too much more intense than 2tblsp.i believe its 1tblsp per gal i could be wrong my memory isn't that well and i cant search.