I tested the parameters in my 300G yesturday, Ammonia 0.0 Nitrite 0.0 Nitrate 0.0 And Ph 7 I'm using the drop test kit, not the strips. Ive been adding lots of fish food and ammonia letting everything rot, could my tank possibly have cycled in less that 4 weeks? It is a really big tank, I added old gravel from one of my smaller tanks and lots of live plants to the set up. Should I do a water change now or add fish into the tank as is? I don't want to do anything that could risk my fishes' health. Also my husband decided to clean the filters last night, and he washed the sponge filter in untreated tap water!!! Shame he thougt he was doing me a huge favour. Would that affect the parameters much or should I wait another week and keep an eye on the parameters before adding fish? There should be enought bacteria in the gravel and in decor shouldnt there?