calcium test of made up instant ocean salt?

[nitrofish]

I have a feeling my calcuim test kit is giving me a false high reading, to test this I would like to test my results against someone elses. I haven't tested yet, but I will make up a small batch of instant ocean salt to 1.025 with ro/di water and test with my hagen calcium kit.
let me know what you get for a reading., im going to go make up a batch right now.

 

[nitrofish]

360 is my test results

 

[~Flighty~]

don't quote me on this, but I think salt mixes can be hghly variable in ca content. the ca can become nonsoluable over time and leave that chunky white stuff when you mix up water.

 

[Chris A.]

That's what i got from IO also.

 

[Scuba_Dave]

On future water changes I'm going to check the CA & Alk 1st, adjust to what the tank is (or should be) & then do a water change.
IO always seems to be "low".

 

[Moe_K]

IIRC, the Hagen test has a high margin of error.
How much does each drop of reagent change the reported Ca level? Is it a 30 ppm change w/ each drop?

 

[Chris A.]

Moe it's 20ppm

 

[nitrofish]

I got a new test kit and its telling me my tank calcium is at 460, hagen was telling me it was 500.