<span class="link_user">@Blabina</span>, It's really cheap and useful, I just connect it to my phone via bluetooth :D payed like 7-8$ for it, from Xiaomi
I don't have many experience with fertilizers, but looks like my plants loved them. I will use AN again, maybe even add some products :) Cal-Mag got a lot of N so it's hard to use in flowering, that is why it's a 4 star.