Curious, do you still have this tank going? I have one of these too. I managed to cram a 5 watt LED 5500K bulb into the existing fixture. Made the tank very bright and sparkly, but I had a hair algae explosion and my shrimp and snails couldn't keep up. Then moisture or something got under the plastic and the bulb went out. Was out for about a week, which took care of the hair algae. I just got a 3 watt replacement bulb, which seems more reasonable. I'm hoping my HC will grow out. It was doing pretty well with the old bulb, but withered quite a bit during the blackout period.
I have one tiny little yellow shrimp in there currently. He is an adult, but just never grew. My wife killed all the others by overfeeding when I was out of town, but this one is a survivor.
And FYI for anyone who finds this thread, I use the TOM Mini filter in this tank. Very quiet and works great. I found that by dumping the tiny bit of carbon that comes with the filter and cutting a piece of carbon filter pad, I could fit it in the holder. Works great for such a small tank, and I change it about once a month. One sheet of the carbon pad will last a lifetime for this filter.