For some reason people seem very focussed on Total Dissolved solids (TDS). Our hypothesis is this is the case because it's easy to measure and the equipment to measure it is not expensive. The truth is TDS is important but it is only one part of an important story.
Too often people read an article or talk to a shop and they are told Keep these shrimp at between 100 and 150 TDS. However depending on what salts you use to remineralise, the General Hardness (GH) generated by that TDS figure changes wildly. We strongly believe that GH holds the key and difference between surviving and thriving. We like GH between 4-5
Our current batch and brand of salt remineralised give a GH of between 4 - 5 when the TDS is at 70. Another brand of salts give a GH of between 1-2 when the TDS is 120. Scarily the same brand but different batch of salts give a GH between 3-4 with the TDS at the exact same 120.
Moral to the story, don't assume that all salts are the same. Don't even assume the same brand is the same from batch to batch. Mix up small test amounts until you get the parameters where you want them. Once you have that dialled in, do some maths and mix up larger batches. if in doubt, test rather than assume.