Fish in the tank? If there are, then you have not cycled the tank. That could be the cause as well. Keep an eye on ammonia and nitrite if there's fish in there, keep the levels below .5ppm.
Most fish stores will test your water for free. So, you could try that.
You might also try to convince your mom that you're interested in the science behind the tank, and that a test kit would help your understanding (and hopefully, it will). Many parents are happy to pay for something educational.
haha that would be a juke ill tell that to my mom but she alredy knows that i pulled that on her to get the tank and everything else so ill try to get it tested
A Bio-Wheel is good because it means you can change filter media without worrying about causing problems. It makes your tank more stable in the long run than a filter without bio media. The Bio-Wheel basically gives the good bacteria somewhere to live with the oxygen and water they need.