If you're going to calculate the T5 as if it's going on a 4 foot tank (54W) then you also need to be reasonable about the application of the MH - no one is going to try to realistically light a 4 foot tank with a single 250W MH. So consider that the above example is likely 2 x 250W MH in a real-world application (although that's purely speculation on my part as I wasn't the one making the claim - but it's certainly a reasonable consideration).

Secondly, very few people actually recommend running T5HO actinic lamps. A typical application would include lamps measured some where around 450nm but generally not pure "actinic" 420nm. And as an example even a 250W AB 10,000K on an M80 ballast has its largest peak at 420nm (actinic) so I suppose it's producing false high PAR readings?

Don't take the half-a$$ed quote as being derogatory. I'm just trying to impress upon people that you can't compare a low end T5 set up to a properly cooled and reflected T5 set up and expect to get comparable results.

You are correct of course. Fair enough, I think the OP will make the right decision and perhaps I'm getting a little carried away. No offense taken, and the OP is considering SPS, so he should get the best he can.

After two days worth of research, posting, checking stores, looking at market value, pricing, etc etc.

I have decided to go with the current usa 6x39 watt nova extreme pro fixture.

It has more than enough wattage for my tank, economical, individual reflectors, dual switch, splash guard, comes with bulbs, tank mounts, cooling fans built in, etc. for 450 canadian dollars. That is the best I think I will do.

Thanks folks, didn't mean to start a heated thread :p

ive tested a few different setups, the 4 foot tanks i tested were under 2 250w's for comparison, the tek i have tested equall to a 400w even, the 400w was a tar ballast and not so nice reflector though, personally i hate how every t5 thread goes this way every time, im just stating facts that ive tested with my own par meter for my own knowledge, if anyone wants to listen great if not fine too my corals are doing great in a 27" deep tank with the light way higher than it needs to be so in my opinion tek lights work great, i havnt yet tested any higher end 48" t5 lights that would make a fair comparison so im still a bit skeptical on how much better the light output is on them, personally i think its mostly name and features like cooling and dimming that make the over double the price

Sounds like a great decision - you've ensured your fixture has the most important components and found a reasonable compromise with respect to pricing and "quality".

I'm not sure why this was directed at me as I was defending your comparison of 8x54W to a 250W while deducing that the tested 250W set up was actually 2 x 250W while Myka erroneously assumed the comparison was to a single 250W.

With respect to the "double the price" comment I agree. I don't believe that the prices charged for the higher end fixtures are necessarily justified as being purely a consequence of quality or features. In most cases fixtures fetch those prices based on brand IMO. But it's also true that there are few "half the price" fixtures that incorporate active cooling, splash guards, quality individual parabolic reflectors, and good ballasts/components.

For some visual appeal is its own performance stat I suppose. The higher end fixtures have the much nicer extruded aluminum shells which I think are well worth the extra money. If you're going to put it in a canopy go retrofit in my opinion.

It is one thing that I am allready sic of in this hobby. The gross overpricing of equiptment once you put "Aquarium grade" on it. Me, being an electrician, Know the costs of alot of things. And I hate it that the same item is cheaper if its for Commercial installations, rather than Industrial. but in reality, its the same darn thing....

Cost DOES NOT allways mean quality

no, not aimed at anyone, personally i like the good stuff and have often payed more for a similar product just cause its cooler(to someone i guess) i like to have a nice looking fixture even if its hidden in a canopy,, like my $600 reddragon return pump im quite shure is just a pump with a fluvalfx5 impeller and i nice housing ohwell its cooler shure ill pay $500 more than a mag pump. not quite shure what part of my brain turns off when i look at aquarium equipment