Fresh2o
Aquarium Advice Addict
^^^ Regarding the EC, I agree with some of your points: it is basically overpriced lava rock granules. Can be a challenge planting small stem plants and carpets (can be done). Out of the bag, the black variety includes small amounts of tan, red, and gray granules; if you are looking for a solid black color then this is not it. However, the color won’t fade; the product I bought over 5 years ago still looks the same. Also, every account I’ve read mentioned it’s high CEC value. I have no way of measuring this property, however, from personal experience my plants did well with minimal root supplements (both stem and heavy root feeders). There was copious amounts of fish waste and I was doing a daily water column get regimen.