I am having an issue with plants getting brown leaves. I have a 30 gallon tank with a fine gravel substrate. I'm running a two bottle DIY CO2 system. 6500k 36" bulb I use liquid and tablet ferts. The lights are on about 11 hours a day and at night im running actinic bulbs. Any ideas would be great. PH 7.9 Nitrite 0ppm Ammonia .25ppm Nitrate 10ppm