Totally Agree.Looks like to me the NO3 is a bit on the high side for the low ALK you have. That has always caused issues in my tanks. Check your MAG is in a good range, as that may make is a little easier to stabilize/balance the ALK and CAL.
I finally (slowly) got my Alk to 7.5. Yeah I've been doing it too slowly, and lost patience (doing tiny dosing increases).
So I just did an extra 20ml on top of Dosing to bring up alk approx. 0.3 daily.
I will continue till I get to to about 7.8-8.0 range and stop. Slightly about 7.5 to give me room to drop.
I know the dosing is now at a point where Alk stays the same.