Hey, I have the 6 gallon with the 42 LED lights and I have HC Cuba in mine.
How is your coverage? I had to supplement a desktop along with the 42 LED because the corners were dark/not bright.
Here is what things to look out for, my HC Cuba got blasted with too much light due to my desktop lamp being focus on them. They got yellow/brown and stunned as I was under dosing.
I upped my K2HPO4 for K and Seachem Iron, so if your Cuba gets all yellowish try that. I have heard the first 2 weeks they dose a lot of K and Iron much like ADA Brightly K.
I'm was running 1 bps and high light with low fert which gave me this:
Not to high jack your thread or anything....I hope your HC cuba turns out better than mine.
1.What colour is your ph drop checker in the morning?
2.Does your betta never get freaked out by the constant reflection?
3.Does he try to franticly find the opening?
4.Don't you get bubbles from the plants pearling?
I feel your pain, this tank has a lot of limitations due to it's unique design.
I'm trying to figure out what the limiting factor is for HC Cuba, I initially thought it was light but it turns out Cuba can do well in medium light.
Co2 and it's distrubtion is much more important, what colour is your drop checker when the lights goes off? What colour is it when they come on?
I think your HC Cuba is lacking a bit of light, yours is growing kind of leggy, mine was spreading sideways due to high light.
Anyways, I would definitely get some Seachem Iron and add K, it brought my colour back to green.