Calcium Deficiency w/bad Ca:Mg ratio?
In a 20H, I've got some signs of calcium deficiencies (leaf tips curling/cupping, some stunted growth, esp in taller plants), and I've started using a small amount of Equilibrium, so my GH is around 9 or 10 dGH (or around 180ppm). But a calcium test shows my water has a pretty low Ca in comparison to the GH - around 40ppm, so the Ca:Mg ratio seems to be off.
Is it possible that the plants are consuming all the calcium, or the ratio is off, and should I be adding pure CaCO3 or CaSO4 instead of Equilibrium to offset the Mg? I've read that high Mg can cause Ca deficiencies.
I've contacted the water company to see if they test for hardness and/or calcium/magnesium. If their tests agree with mine and the Ca/Mg ratio is off, should I soften the water and then add back the right balance, or find another source of water? (RODI is not an option).
or am I over-engineering it all?
Side note: all other params are where I expect: 10-20ppm N, 1-2ppm P, plenty of K, 30-35ppm CO2 via reactor, Finnex 24/7 light.