i would have to say kh.that is way on the low end of the chart.i run mine between 10-11 and if it drops below that the very first sign is less polyp extension and color looking off.as long as you are not dosing carbon i would say slowly raise the alk.if for no other reason then to get it at least in the mid accepatable range.where you are now if you have a drop for any reason there is not much tolerance room.just my opinion.