I'm currently using a 15 minute ramp up and down within my 6 hour photoperiod. I'm fairly convinced that light is my restricting factor right now, but then I know that is the biggest newbie mistake that I can make and I turn it up and could get algae. My alternanthera is really slow to grow and is green rather than red. My hydrocotyle tripartita is almost non-existent on growth. It took time to get established, it was tissue culture and all the emmersed growth died back and I have cleaned all that out the tank and just have the new submersed growth, but it is tiny, the leaves are about 5-8 mm wide and each stem is less than 3 cm tall and it just sits there quite happily, not melting, but not growing. It's close to the front, gets flow, I can see it moving, drop checker is green, I'm dosing EI, its in the front corner so not as bright light as other areas, but its not shaded. According to Tropica its needs are low CO2 and medium light, so I can only assume that light is the restricting factor. I think another interesting point is that all my smaller foreground plants, the Hydrocotyle, the Ranunculous, the Alternanthera, the Monte Carlo and the S. Repens are ALL bending forwards towards the front of the tank, which looks to me like they are reaching for the light from the window at the far side of the room and that is their dominant light source for most of the day, the lights come on in the evening at 17:00.
How high have you mounted your tile above the water and how deep is your water? My tile is quite high, about 30 cm above the water and my water depth is about 40 cm, so not only am I running at 20% intensity but it is a good 65-70 cm from the plants. I'm tempted to try a little higher on either intensity or duration as I am algae free apart from a couple of tiny bits of diatoms, but I am reluctant to increase both together, so would really appreciate some more input from people on this thread.
