my tank is a 125gal and only housing 1 6" jardini and feed it only once a day with 1 frozen shrimp or 2 shrimp depending the size of the shrimp. my nitrate always climbs up to 40ppm in a week after a 50% water change. I got 2 110aquaclear and 1 fx6. any ways to lower the nitrate or slow the climbs of nitrate? I got 1 plant in the tank.