[header] How to mix hydroponics nutrients [title] Know what's in your water. [step] Send your water to a lab to be tested, if you can. With good, " soft " water, you'll be able to add any nutrients your plants need for their optimal growing season. 
With " hard " water, you may need to use reverse osmosis methods to filter out any unwanted heavy metals present in your water. [substeps] You can also use a dissolved solids meter to check your water regularly.