Well, it's a good surface area if you don't have a filter in the tank. I don't have filters in 2 of my betta tanks. The gravel, plants, heater, etc. provide enough surface area for the bb to grow. It all depends on the size of the gravel and how much you have. Also, I never said that it was necessary to have substrate. I just say that I use gravel.
I don't think substrate is the reason a tank can cycle without a filter...there's other ways to provide surface area. I've never heard of a tank cycling wihout a filter anyway but I'm not going to argue against that...
Well, it's hard to find a small filter around here. Not only that, but I don't see the need since my bettas don't react well to filters. The only filter I have in a betta tank is my 10g divided, but it has a male plakat on that side.
Oh really? Then why did 5 of my past tanks cycle with nothing but gravel, an airstone & plants? Cycling misconceptions run deep it seems. Anything in the tank can hold beneficial bacteria. Even did this on a 29gal goldie tank.
An airstone provides aeration (oxygen). and circulates the water over the bacteria for treatment. A filter literally is not necessary, a simple pump will do. While it is true that anything in the tank will hold bacteria ---even the livestock--- a filter is a great way to get particulates out of the water and provide additional surface area for the bacteria in a high-flow environment.
Planting the tank, reduces the need to rely on the nitrogen cycle for ammonia control.
There is always some circulation in a pond, from thermal effects, wind, etc.
Cycling misconceptions abound, agreed. Among them is believing that a nitrogen cycle will flourish in the absence of circulation, oxygen and sufficient surface area.
Cycling is always worthwhile, in my opinion, not for the convenience of the keeper, but for the health and safety of the fish.