Hello there. I am trying to buy some Jacks nutrients online. It is a tad confusing at first on their website. They say for running tap water you need Jacks 15-5-20 Tap Jacks 10-30-20 Bloom and Jacks 7-15-30 Finish. And lastly their epsom salt which is NOT on their website that I can see. My question is would it be fine to just use the organic epsom salt that I already have? Sorry if this is a dumb question.
What's your tap water like? EC/PPM?
The only product you *need* to buy from Jacks (or Jacks branded I should say) is the "base", eg: 5-12-26, or 15-5-20 Tap, or whatever the RO version is. Calcium Nitrate is the second part, and is very cheap, so is Magnesium Sulfate, and both should be easily available. The MgSO4 isn't even needed really, depending on what you're growing in, and the ratios you're using. Eg: Jacks 5-12-26 already has magnesium sulfate in it.
Check out Renfro's nutrient calculator (or an online "elemental nutrient profile calculatore" like canna stats) if you wanna get an idea of what's actually in various fertilizers and ratios and stuff. It's worth it just to understand the concept.
Good luck, dude.