Magnesium at 900

johnnyenv · Feb 25, 2017

Hi,

According to my tests my MG is at 900. Using a calculator it's saying I need 600+ tbspns of MG to get back up to 1250!

Not sure whats happening here as thats just plain ridiculous.

DKH - 9
CA - 500 (I'm aware thats a bit high).
Salinity - 1.025

Any thoughts? I must admit I didn't think MG was that low but I have tested multiple times.

Randy Holmes-Farley · Feb 25, 2017

Testing error. It never gets that low.

What kit?

johnnyenv · Feb 25, 2017

One of those from the JBL marine kits.

Randy Holmes-Farley · Feb 25, 2017

I don't know much about it. Don't boost the magnesium at this point.

What salt mix?

johnnyenv · Feb 25, 2017

Randy Holmes-Farley said:
I don't know much about it. Don't boost the magnesium at this point.

What salt mix?

Aqua One Pro

http://www.aquaone.co.uk/marine_aquarium_salt.php

Randy Holmes-Farley · Feb 25, 2017

The only alternative to bad test result is bad batch of salt. That's a lot less common than bad test results.

It didn't get consumed in the tank down to that level.

johnnyenv · Feb 25, 2017

Right I have used this JBL test kit on my aquarium and its calculating that 15 drops =1,400 which is before the deduction of calcium. I've used the same kit on a freshly mixed 200l of saltwater at 23 degrees (Not quite up to temp) but thats also coming out at 1,400 before the deduction of calcium. I have a Salifert test kit which is one year out of date and that thinks the magnesium is at 1,500 which doesn't need deduction of calcium I don't think?

So my in date test kit appears to be miles off and my out of date one appears accurate?

Randy Holmes-Farley · Feb 25, 2017

johnnyenv said:
Right I have used this JBL test kit on my aquarium and its calculating that 15 drops =1,400 which is before the deduction of calcium. I've used the same kit on a freshly mixed 200l of saltwater at 23 degrees (Not quite up to temp) but thats also coming out at 1,400 before the deduction of calcium. I have a Salifert test kit which is one year out of date and that thinks the magnesium is at 1,500 which doesn't need deduction of calcium I don't think?

So my in date test kit appears to be miles off and my out of date one appears accurate?

Correct, the Salifert needs no calcium subtraction. Also, there's no way to get magnesium by simply subtracting calcium from a general hardness kit. It cannot work that way. There must be a multiplier on the calcium result or the magnesium result for that to work since the units of measure are different (we can get into why, but I doubt it is worth the discussion at this point).

johnnyenv · Feb 25, 2017

So apart from the Salfiert test kit being out of date its likely my MG is within the acceptable parameters? I think I'm just going to get a new Salifert test kit and be sure. The rest of my kits I'm changing for Hanna checkers.

Thanks Randy Homles-Farley.