After a bit of searching this is what I came up with for a simple DIY solution:
To get a 2000ppm solution would need to put 2g of table salt (NaCl) into 1L of RO water.. or just put 1g of salt into .5L of RO water. Dilute accordingly for a range of solutions, just be careful to measure accurately and STIR IT UP WELL.
I based this DIY TDS solution recipe on How to Make Calibration Solutions.
This link can also teach you how to make a TDS meter if you are feeling handy.
Not sure if this is accurate. I did this (2g of NACL in 1L of RO water) and two meters gave me a value of exactly 1500 ppm. Either both of them are identically wrong or there is a problem here. I tested it many times at room temp.
ReplyDeletebecause we want to get to low ppm calibration levels, the better way is to make initial solutions with high concentrations (20000ppm) using 20gms in one litre of water, then dilute the initial solution, appropriately. This is because if you have a suitable scale, it is easier to measure 20gm accurately than 2gm. Dilution by volume or weight is then a more accurate way of getting to lower concentrations. Once fully dissolved, take 100ml of the original solution and make up to 1000m (1 litre)and this will give you 2000ppm, then mix this solution well, and then repeat, take 100ml of the second solution, and make up to one litre. This will give you 200ppm. Repeat appropriate dilutions to get 100ppm and 50ppm and 20ppm.
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