Question about magnesium test

muddy tdi · Oct 30, 2014

Hi I am new to reefkeeping and at present time I am cycling my first reeftank. I am using Salifert magnesium test but having trouble! The colour wont change from pink to blue when I empty the whole second syringe into the tube so my question is this : does it mean that my magnesium is high or low? I used ro/di water and Redsea coral pro salt which says that is has a mag of 1340 on the bucket.
Thanks in advance.

Greenstreet.1 · Oct 30, 2014

I would not worry about mag yet if you are cycling just nitrate nitrite and ammonia. But to answer your question it looks like it hi if you did not get a change in color.

muddy tdi · Oct 30, 2014

Thanks for your reply Greenstreet .1. Yea you are right but I am about half way of my cycle process so I have to start thinking about other parameters such as calcium and mag. Anyone experienced this same issue please? Should I rely on the Salifert mag test? I mean is it accurate?

Randy Holmes-Farley · Oct 30, 2014

Agreed. The magnesium level in your water right now will be exactly what is supplied in the salt mix you are using. It depletes far, far more slowly than calcium. If you are not adding a lot of alkalinity and calcium supplements, magnesium is not being depleted.

I've not used the Salifert magnesium kit for quite a few years, but it does work fine.

If you have added two full syringes of titrant and did not see the endpoint, something is wrong.

Try measuring some RO/DI water (or other fairly pure fresh water) to be sure you are recognizing the endpoint and it is working OK. It will happen almost right away with RO/DI water being tested.

muddy tdi · Oct 30, 2014

Thanks Randy, I am not dosing anything right now, what I cannot understand is the fact that the test kit is not showing the 1340 as it is written on the saltmix! I will try and test some ro/di water later and will see. I have 0.5 phospates, could that have any effect on the magnesium test??