double ended mh bulbs vs screw in type

[BrainVat]

Originally Posted by Samw

Its a myth that DE lamps produce more light than SE lamps.

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.