So I have had an aquarium running for a year plus now. It's a 5 gallon freshwater one. Before today, it was home to countless pesky snails and my nerite. When I measured the water params before cleaning, the readout was over 20 ppm. This was not ideal for the betta I added today, so when I woke up in the morning, I did a full water change and deep cleaned the gravel. I have also removed a large number of the invasive snails. Because of the effects it may have on the microbiome, I left the hanging filter alone. I cleaned the sponge/bubble filter though. (Yes I have 2 filters) did a readout an hour ago, and I'm reading 0 ammonia, 0 nitrites, and 5 nitrates. My question is this; do I have enough biofiltration in my tank to accommodate the betta comfortably? How closely should I monitor the specs of the water levels?