I'v searched around and found a little help to this question, but nothing really covers my exact scenario. Just setup my new tank. Have some live plants, all stem except for a couple wendtii's. The planted tank geeks at the LFS recommended some root tabs for a few of the stem plants as it would help them root in. I used 5 API tabs in the 65 gallon (way less than they say), pushed them all the way in the substrate. Since I used seeded media for the 'instant cycle', after 24 hours with fish I tested water and had 0 amm, 0 nit, 40 nat. 24 hours later 0 amm, 0 nit, 80 nat. After some quick searching here, I vacuumed out the tabs and done a 50% water change. 12 hours later another 50% water change. Now readings are 0,0,20. Question is do the API tabs really cause a huge spike like that? In theory I had about 1/4 of what the package recommends. According to the API website, root tabs have 3% nitrogen. Flourish tabs have 0.3% nitrogen. So I presume the flourish ones are less likely to spike? Do I even need root tabs for the couple of crypts or shall I just stick to using flourish liquid and leaf zone? thanks for any input.