I fixed the thread width issue, hope that helps.

But those were different ballasts. You had the high powered M80 whereas mine was using only 250W. :smile:

But yeah, I checked out Sanjay's link there with Coralvue bulbs and the Coralvue SE bulb also had higher PPFD than the Coralvue DE bulb using the same ballast and same color temp bulb.

http://www.reeflightinginfo.arvixe.com/select2lamp.php

but my point was they were both sold as HQI ballast. yours was an electronic ballast which at the time we though were just as powerfull but now we know different. at anyrate lots of data shows that with out reflectors the SE is a more powerfull bulb.

Steve

my next question is what would you recommend for a 44g pentagon shape
tank, total depth is 23" from the top. would 175watts be enough?
or go with the hqi 250w?

thanks
rob

But Steve, if you're mixing and matching like that, what if you had a DE and I had an SE? Your DE on the M80 would still outperform my SE on the IceCap ballast. So in that case one might think that the DE was better. But in fact, you used a different ballast which would produce more light than the IceCap regardless of bulb type. That's why you have to keep the ballast constant when making comparisons of bulb types (with same color temp).

Enough for what?

I'm pretty sure the 250W would be better. If you use a DO meter to test photosynthesis (oxygen output), I'm almost sure that you would have higher DO with the 250W bulb. In other words, the extra light is not being wasted and is being used for additional photosynthesis. That's the case in my tank anyways which is full of photosynthetic animals.

And it goes without saying that all this depends on what you want to keep. If you aren't keeping anything very light demanding, then the 175W is probably enough.

um there were the same color temp weren't they.

Steve

Yes, they were as far as I know. 10K AB.

ok had me confused for a sec.. not hard to do these days it seams :rolleyes: :mrgreen:

Steve

Not entirely. For example, comparing a radium SE to an XM DE shows that the SE bulb gives off more light. But within a given brand, it's most often the case that DE bulbs produce more light than SE at the same wattage. This is the case with XM lights and also true for Sun Aquatics lights with the exception of the 10k series.

Try formulating intra-brand comparisons with sanjay's data to verify that this is true.
http://www.reeflightinginfo.arvixe.com/select2lamp.php

By this data, the myth seems to be that the "rule" for DE vs SE is true for all bulbs in all cases. More accurately, it is a simple general guideline for a given brand name that has some exceptions.