[jooo]

Hi there! I am making HSA media to grow algae. The recipe is here: https://www.chlamycollection.org/methods/media-recipes/hs-hsa-and-ya/. The media is made by the mixture of 4 different nutrient stock solutions (complete salts, sodium acetate solution, phosphate solution, and Hutner's trace elements). I am feeding the stock solutions into an algae bioreactor but the reactor only is capable of handling 3 nutrient inputs, not 4. I need to premix 2 of them but want to mix the two that will be least likely to react / degrade when mixed. I started by trying to make the acetate solution (sodium acetate tetrahydrate) and complete salts solution in the same solution. Instead of making acetate stock at 400g/L of the hydrated salt in water and making the complete salts solution as 100g NH4Cl, 4g MgSO4 ∙ 7H2O, and 2g CaCl2 dihydrate in 1L, I added 400g sodium acetate + all of the complete salts solutes to the same beaker with 1L water. The reaction is extremely endothermic. Are the contents of my reagents degrading / reacting with each other and will I no longer have functional components? Why is the solution getting so cold? Which stock solutions would be ok to mix without them reacting?

[wildfyr]

It just has a positive heat of dissolution. As long as everything dissolves, no reagents are being harmed and your solution is fine..

The "safest" ones to combine are probably ammonium chloride and calcium chloride. That will make sure nothing precipitates.