A simple tired and trusted way to make hydroponic solution for growth of a variety of plants. Link to order calcium nitrate, https://campbellteaching.co.uk/calcinit/186/1kg-yara-calcinit-calcium-nitrate-fertilizer-15.5-0-0.
For hydroponic nutrient solutions I make everything up by volume, rather than weight. I add 15 mls of the calcinit (calcium nitrate) to 100 mls of warm water. This dissolves in the water. I then use this as my stock solution. I dilute this 1 part into 250 parts of water to give my final solution.
I then add the same concentration on NPK fertiliser with trace elements. That is, 15mls of NPK fertiliser dissolved in 100 mls of water used as a stock solution, added to the same 250 parts of water I have just added the calcium nitrate to.
I also add magnesium sulphate (Epsom salts). I make the stock solution up with 7.5 mls of epsom salts in 100 mls of water to give the stock solution, this is also added to the same 250 parts of water. Again, one volume of Epsom salts to the same 250 parts of water.
If you like you can mix the stock solutions of Epsom salts and NPK fertiliser. However, it is best not to mix the stock solution containing the calcium nitrate as it can precipitate. When they are all diluted in the 250 parts of water it is diluted enough not to precipitate, and it is fine.