"Thanks Vlad. I'm setting up a new GB and am going to use lava rock for a base media and top it with hydroton. I have year old GB that has always run around 7.2-7.5pH. I'm thinking about transferring some of the Growstone in that bed to see…"
"It doesn't matter, the color of the vinegar...you can use any type of acid (doesn't have to be vinegar, it's just that vinegar happens to be what most folks have on hand) to test your media for limestone (CaCo3). You're looking…"