I use 4 fixtures, with a dimmer switch and timer. That'll take care of the heating issues.Yup I know the difference. One is color temperature and the other is intensity. Most people suggest 6500k being a good temperature but I also read somewhere HC (what I'm trying to grow) take on full sunlight.
I'm actually mixing 5 LED plates with different specs on my DIY light. The middle one has white and blue (450nm) lights (20 leds), wrapped around by two red (660nm) and blue (440nm) (10 leds) and then two white lights each with 10 leds. Total power consumption is 140w.
I'm definitely having more lighting than I need and it turns out the heat generated is also causing issues so I need to hang it higher up and possibly add a dimmer.
They're never all on at the same time. 1 timer shuts off 1 light and another timer turns the next 1 on. I did it to simulate morning, noon ,evening and moonlight cycles in the day.
Accidentally, I discovered it solved 90% of the problems I had with algae growth, heating issues (as you described), plant growth tripled and the fish seemed happier, healthier and less stressed.