OK, so just in the last two weeks I have noticed troubling symptoms beginning in my swords and java fern, and to a lesser extent my bacopa. The leaves when they first appear are almost transparent. After a few days they darken up, and the leaves remain brittle. Sometimes holes appear in the leaves, almost as if the leaves have been worn away. Sometimes new leaves have a yellowish cast. I have had the plants for several months and they have been doing very well. The tank is 30 gallons, nothing has changed except the addition of 3 new neon tetras. The pH is 8.0. I suspect the problem is nitrates being too low (usually 10 ppm or under, and dropping lately) but am not sure. There are no nitrites or ammonia and I change 20-30% of the water weekly. Lighting is 2.5-3 wpg. I dose with flourish every day, kent freshwater (0-0-3) 1 tsp per week, plant grow by nutrafin (.15-0-0) 2 tsp per week. There are root tabs placed about a month ago for the swords. The tank is quite heavily planted. Any thoughts? I really appreciate it.