Opinion: 250W or 400W?
 

If you had a 50 gallon SPS cube and had the choice of a 250W-DE HQI or 400W-SE, which would you choose? Would 400W be overkill?

What are the dimensions? 24x24x24 ?

I had a 30x30x30 cube (115g) that I lit with a 250w DE right over the centre. It worked well enough for me.

If I were to do it over again or over a 24^3, I'd go 250 again, but I'd probably flank it with t5's or LED's to give a little more oomph and dusk/dawn variability.

It'll be over my 24x24x20 cube. Both fixtures have 4xT5 (main reason why I'm considering the change are the actinics themselves... this lead to finding some nice fixtures).

I would go with 250 watt. A 400watt might heat up your tank a bit too much and I don't think it is necessary with 20" high to have more than 250 watt. I have 250 watt and have very good results with my SPS, even in the middle of the tank and mine is 24". The fact that I have 250 watt also let me put some zoanthids at the bottom without burning them up.

It's only 20" high? Definitely save yourself 150w, 250w will be fine.

I would use 250W DE on HQI, will be more than enough.

Thanks guys. I was already leaning that direction (already have 250W) but have never used 400W SE before, so I was curious.

You will also save a little on the price of bulbs.

Agreed on both accounts, my 400W was WAY to powerful and it was on a 30" depth tank. It was also a DE which is almost impossible to find, was looking @ almost $200.00 for a new bulb!

250w....but you will need supplemental and be careful of those crappy de pendants.