The T5 bulbs that you have sound fine, but may not be that great. The 18K one is suspicious to me. Also if these were Giesemann Midday T5HO bulbs I'd have no doubt you have enough light. With all other bulbs you just need to see if they work for you. And you will always need much more wattage with all other bulbs compared to the Giesemann's.
The sump is making the CO2 fizz out of the water at a rate that you don't even suspect. With bioballs and water raining over them I'm surprised you have pH of 6.6 to 6.8. If you have an acurate way to check your pH please double check this 6.6 - 6.8. But it's always better to watch the plants and the tank itself to draw conclusions.
And 2 more things:
- How tall is that tank?
- How long is your photoperiod?
--Nikolay
The sump is making the CO2 fizz out of the water at a rate that you don't even suspect. With bioballs and water raining over them I'm surprised you have pH of 6.6 to 6.8. If you have an acurate way to check your pH please double check this 6.6 - 6.8. But it's always better to watch the plants and the tank itself to draw conclusions.
And 2 more things:
- How tall is that tank?
- How long is your photoperiod?
--Nikolay