Sorry, I completely forgot about this and sold my tank since. Might be getting back into the hobby in future though.
Aquaforest was correct that the main culprid here was the test kit by Salifert, which is fair enough.
Salt bucket batch serial stats: 1308.
Marinlab test results: 1462.
Salifert test kit: 1500.
I don't think home grade test kits are made to be that accurate. So the Salifert kit reading 1500 when it actually was 1462, is actually not that far off thinking about it in hindsight.
In Aquaforests' defense, the salt MG level was not actually between 1500-1600 as per my original statements. However, it still wasn't accurate to the batch. It's now been years, and I no longer have a tank (at the moment), so happy to put this to bed.
I think the take away is, hobby grade testing kits only go so far (which is what AF rightfully so was telling me), and the batch testing by AF can probably also just be accurate up to a certain point. It's not necessarily gospel.
In future I will ignore MG if Salifert reads 1500 and rely on ICP tests every few months for an accurate reading.
I will let someone else take up the challenge of working with Salifert on why their MG test reads the way it does.
cheers for that.
Thinking on changing to aqua forest as my present salt has shot up in price.
I use the Salifert test for mag and find it good, if salinity is slightly out or you don’t stop at the start of the colour change then I can see why it would read high, I feel Salifert might be showing a dramatic colour change when it’s only a slight change that is need, I know on their alk test that is definitely the case.
