I first the first time in years starting checking my levels these last few weeks. Those of you who know for the time being my tank is way overstocked and ill admit it.. Never have any ammonia but no matter how much I change the water I maintain a constant nitrate level. Not horrible but its def there. Any advice to get it away without removing some of the fish LOL? Add more bio to the sump maybe? No fish seem stressed and Im guessing its always been like this but just recently I started checking since now I have over $10k worth of livestock...