First post here. I’ve recently gotten back into the hobby after a 20-year hiatus with a 20g Waterbox cube. I’m one week in, have 20 lbs of "live" sand and about 20 lbs of "life rock". I started the tank cycle with a clown and a psuedo (please don't nag, I did the research and decided to cycle with fish and additive bacteria). Over the course of the first week, I added bio spira, fritzyme 9, & dr. tim's one and only. Yes, it might be overkill but I believe the more the merrier to jump-start the tank since real live rock isn't really an option anymore and so far I am very happy with the results. Everything is going great and the cycle was done in five days (ammonia- nitrite spike and back to zero, nitrate steady at bout 15 ppm). I stupidly decided to rotate the aquascape this morning and in addition to a huge cloud of sand dust, I noticed literally thousands of bubbles flying to the surface as I spread the sand bed back out. Do you think these were still trapped from the initial set-up or a result of the nitrogen cycle?