40 Litre Tank Just Won't Cycle :/

[NewToFish1989]

Parents decided to get a 40 litre tank to keep a small school of neon tetras and asked me help them cycle it. I added 4ppm of ammonia 2 weeks ago and since then nothing is happening and done everything exactly the same as I did with my large tank.

My large 160 litre is almost done and that's been cycling for nearly 2-3 weeks now. They got a all complete which came with a submergible filter and not a external one and I'm guessing is the submergible filter simply not strong enough to cycle or because its smaller, its going to take even longer.

 

[Caliban07]

You have to keep adding ammonia. I would only add 1 part though every couple if days. When you eventually get a nitrate reading. Gradually increase to 2ppm for a week then 3 then 4ppm. When ammonia goes from 4-0ppm in 24 hours and you have 0 nitrites and a nitrate reading below 20ppm you are safely cycled.

As long as the filter output flow is at least 4 x the size of the tank then the filter is fine.