Originally Posted by Ktran350
Hey guys. So I think I might have an issue with cycling my aqurium. I have a 20 gallon with a external 150 marineland filter with two filter media and and a Grreat internal filter stocked wih 8 with danios, 4 guppies, 2 gourami dwarfs, 4 Cory catfish and a few ghost shrimps. I've had the tank set up now for over a month. On Sunday I tested my water and it showed no ammonia, high nitrite and nitrate levels. I did a 50% water change and like an idiot replace all filter medias but left the bio wheel alone. I tested the water Monday and it showed no ammonia or nitrate but high levels of nitrite. So i went and got 5 live plants and a bottle of prime which i treated the tank with. Yesterday i tested the water and had no ammonia or nitrate but still high nitrite. I than treated the tank with prime and added a whole bottle of ATM colony (per petco) and label than this morning I tested the water and now it's zero on ammonia, nitrite and nitrates. All other parameters are good. Is the tank cycled now or did I Messed up the cycle? All the fish seem fine they are active and eating. I am using the API freshwater master test kit. Can anyone advise?
My advice is the plants and bio wheel did more for your aquarium than anything else.
The plants will consume the ammonia directly while the aerobic bacteria build up. So youcan get no or very low short spikes. Then as bacteria build up there is less and less ammonia for the plants so they start consuming the resulting nitrates.
You can have (if the tank got ahead of the plants) persistant nitrite spikes which are best handled imho by not adding food to the tank to limit ammonia production.
IMHO a tank is never completely cycled and you do have more than just a fish or two. but you do get to the place where the cangerous spikes are a thing of the past or never showed up to begin with.
But that said it sure should like you are on your way with the fish being healthy. I would limit light and feeding so the water stays clear but overall sound like a good setup.