Questions - Need some input

Prologue

I have been at this hobby for the past 8 years (coming up). I have had sucess to varying degrees, which magically corolate with overall interest (aka: Husbandry).

I must admit I am cheapskate (to a certain degree). As well as an advocate for "why pay for something that I can do myself?"

I have a 125 gallon tank with 55 gallon sump, that is filled two thirds for about 160 gallon total volume. I have a Aqua C EV-180 protein skimmer. For ...

hey so i tryed out my new hanna calcium checker and got a reading of 600 which is the max on the checker?

any idea why this may happen?

so the time has come for me to replace my test kits as they have dried up and or expired.

has anyone got anyone got any recommendations?

i may actually get round to posting something pertinent on here soon.

John

Looking for a skimmer that will handle 2 x 80 Gallon Frag tanks with maintainence fish.
I am considering this as the local reef shop recommended it, but I want more than they're opinions.

Reef Octopus Super Reef 2000 Internal Skimmer

How long can one keep pre mixed saltwater in a holding container befor using it for water changes?