No matter how often I do water changes, I always seem to have a ton of junk come up with my Python through the gravel. Also, I am having big Nitrate problems. I have a 30 gallon community tank and can't seem to get my nitrates down any lower than 10 ppm! I checked the water straight from the tap...0 ppm. I did a 50 % water change today and the nitrate was still high. I have lost 4 fish this past two weeks and think it must be the nitrates since I checked all over levels and they were fine. I did about 80-85 % water change and the nitrates are still 10 ppm. I know 10 isn't super high...but is it a good level for the tank? The fish that died looked fine, until they stopped swimming and were dead the next morning. They didn't all die the same night, just over the course of two weeks. There were no signs of disease on any of them. I have heard that undergravel filters help fight nitrates because it is constantly filtering the gravel. But I have also heard that there are problems with them. What do you guys think? Thanks!