I have a 10 gallon that has been set up and cycled for well over a year. It once had 3 males, but recently it was just down to 2. I moved one to a new tank a few days ago, and then moved the other one today. With the suddenly empty 10 gallon, I decided to get 8 guppies. Without thinking about stocking the tank too quickly, I added the guppies. Now I'm worried that the cycle won't be able to keep up with the sudden increase in bioload. I usually change 50% weekly, and I did that today before adding the guppies. I do have a liquid test kit. Should I be worried? How often do I need to test the water? Should I do an extra water change? How much?