The solution to pollution is dilution. Only small to moderate amounts of pollution is needed to establish an adequate beginnings of a biological filtration system. A mini cycle is a problem induced by overstocking commonly, and if you initially overstock any thing but a very mature system you will get a mini cycle. The solution to that problem is all make small additions of stock to your tank, not by trying to establish a "super" biological system with your first cycling. Always error on the side of water changes. It is sorta like if you find a diabetic unconsious, you should always give them sugar. It could very likely save their life, but if your wrong in that treatment it will make almosyt no difference. The results will, at least, give you a clue to what is going on. Water changes are a reefers besr friend. Just make them small and frequent unless there is a catastrophe which might cause the need for large water changes. This however is not common. I like 5 percent twice a week, or at the least 10 percent once a week. Small water changes are very simple to make in comparison to large ones. It should be very simple with a tank as small as a 30 gallon. As you have after displacement for sand and rock you only have around 22 to 25 gallons of water (also consider most tanks will not hold their stated gallonage). I personally would just change a gallon every three days. With a small tank changes can happen rapidly in comparison to large tanks, so the practices of a large tank person does not always reflect the needs of a small tank person. Frequency of monitoring and water changes, as well as filter maintenance and such are more necessary with small tanks. That is why large tanks are more commonly successful. They allow poorer maintenance and more errors without resulting catastrophes.