What is your tank equipment? filter? total flow gph?
According to James's Planted Tank.net the cause of the problem is:
In a high light tank it is an indication of low or fluctuating CO2 levels or not enough water circulation around the plants. In a low light tank it is often due to changing CO2 levels.
If you got your co2 worked out, I think you have a low flow problem in the tank.
I would recommend leaving your co2 constantly on like 1-2 hours on before the light goes on and 1 hour before the light goes off.
Filter: Fluval 406 (383gph)
Powerhead: MaxiJet 900 (230gph)
Both of these put me at 613gph
I'm also already turning the CO2 on before the lights turn on, and vice versa. DC is pushing yellow, maybe changing the flow up a bit might help