Does the lab grade have any sediment in it? I have some tech-grade sodium nitrate powder I've been using, but it has stuff that settles to the bottom of the container. Always need to shake it up before use. I'd like set it up to dose via an Apex, but not looking to have to put it on a stirrer before dosing.you may be good candidate to dose then. I use lab grade sodium nitrate myself now going on well over a year. Pm me if you'd like some details on where to get it and dosages.