Sodium Hexametaphosphate Solution

Feb 2018

I'm not a chemistry person but I am looking for some help to ease my curiosity. I need to make a dispersing agent and the only instructions I have are as follows:

A solution of sodium hexametaphosphate shall be used in distilled or demineralized water, at the rate of 40 grams of sodium hexametaphosphate/liter of solution.

In the past I have added 40 grams of SHMP crystals to 1L of distelled water and mixed. However, it doesn't dissolve completely. I'm not sure I'm doing this correctly.

Can anyone offer some suggestions?
Mar 2018
You can try heating the solution but it will probably percipitate when cooling. In this case you can't solve more SHMP and the solution is saturated.