Randy,"Approved" is meaningless. Who's doing the approving?
My recommendation is to dose inexpensive food or ACS reagent grade sodium nitrate.
I’ve been researching the web for dozing Nitrates and you come up in every post I looked up so I hope you can help me select the proper sodium nitrate. I’m from Canada and NANO3 seems to be very hard to come by. I found this product which is ACS grade. Here is link to the documentation. If you could check it out and share your thoughts:
It’s mostly the PO4, heavy metals and Iron listed in ppm when all other items are in %. That I am unsure. The Assay calls for equal or higher 99.0%.
Thanks in advance for the help!