150 Gallon Tank
I figure I should actually test out my water.

For those wondering, I use Salifert for Alk/Ca/Mg and Hanna checkers for Nitrate (HI782) and Phosphate (HI772).
Major elements were a little low and I'll adjust those over the next couple of days.
Alk: 6.2
Ca: 410
Mg: 1200
Nitrate: 0
Phosphate: 0.11
I was actually surprised to see NO3 and PO4 so low since they were 16.9 & 0.2, respectively, 8 days ago before adding chaeto to the fuge, but it looks like the fuge is doing what it's supposed to be and now I'm nitrate limited in reducing phosphate down.