Greg's 75g

[mrhasan]

I would trust salifert's reading. Despite having junk hardward (the syringe reading with fade away with use), I love how consistent they are with all the test. I never got any surprises till now from salifert (other than the quality of the 1ml syringe).

Alongside, I don't think 400ppm and 7.7dkh is problematic. That's the exact parameters of my tank. But I am starting zeovit so that's justified. I think its more about the balance of ca-co3 than the magnitude itself; as long as they are within the acceptable range.

Balanced Calcium and Alkalinity: (as per Randy Holmes-Farley)

360 ppm to 0 dKH
370 ppm to 1.4 dKH
380 ppm to 2.8 dKH
390 ppm to 4.2 dKH
400 ppm to 5.6 dKH
410 ppm to 7 dKH (natural seawater)
420 ppm to 8.4 dKH
430 ppm to 9.8 dKH
440 ppm to 11.2 dKH
450 ppm to 12.6 dKH
460 ppm to 14 dKH

When I used to run non-ULNS, I concentrated on keeping my parameters in the correct ratio (11.2dkh and 440ppm was my preference). HTH