whats the difference between....

You might be ok with a tank that size with the lights you have on order. Just put the more light demanding corals up on top.

 

wont keep sps under a 150W unless you keed some under the light and easy soft corals around..
but you can use a 250W on a 30g tank w/o troubles it's just 2w/liter so not so much.. we go from 1w to 4w liter so from 4 watt gallon to 16 watt gallon on our tank depending on what sps you will keep and what colour you want..
some special sps will require much more light and some just few to survive.. like tubastrea wont require much light and an acro or seriatopora or (etc..) will ask you the direct light of a 400W..

i had an istrix that was growing too much under the 400W and i moved it between the 250 and the 400 to "reduce" the growth.. and an acro that under the 250W didnt grow.. but under the direct light of the 400W was marvelous purple..

just depend the sps.. but.. more light makes easier the location of sps

 

Soft and leather corals are one in the same(acronym). I would refrain from purchasing Acropora and maybe try Montipora Digitata instead as Montipora is easier to maintain for the most part! It is a nice small polyped stony.
For the most part, LPS's are easier to keep than SPS's. The main reason for this is the amount of light PAR and PUR(intensity) required by many of these SPS's!

 

Thanks for the advice - i think i'll just stay away from sps entirely

 

I have several types of SPS including several Acro's in a 20g long and I am only using 216W T5'S and they are growing great. I have 4 Different Monti's, 3 different colors of birds nest, A green and brown Pavona cactus, and several to be determined SPS frags...

I will agree that they require allot more attention than soft corals, better water conditions and such though. LPS are allot easier along with the soft corals. And I agree about the Montipora's they are relatively easy to take care of. As it has been said it all depends on the SPS.

 

t5 has more lumen/watt ratio..
your 216W have more lumen then a 250W MH.. so you have enough light power ;-)

 

I have a 20L I am getting setup with T5's. How are you getting 216W?
I figured I could only fit 4 24" bulbs which would be 39*4=156 or can you overdrive those 4 bulbs to 216?

 

I made that decision long ago and could not be happier.

So many beautiful soft corals out there...

Much more light tolerant. Even thrive better in crappy water. (not that you want it to get that way for other reasons...:-/)