Solubility depends in part on the form that your potassium nitrate comes in. Some is intended for being mixed in soil and is less soluble than others. You need a specifically water soluble form. Any solute has a saturation level and usually will only reach partial saturation unless the temperature of the water is increased.
Thanks I made new solution for lowlightweekly
200ml to 55 g. Kn03 Dosing 40ml weekly,will give me 10ppm of n03
This will last 5 weeks