Metal Halides

[SA-DSM]

What is the difference between single ended, and HQI? And which do you think is best.

[alton]

HQI needs a lense for UV protection, SE does not. In my case SE have lasted longer than DE. I switched from DE to SE. Now all my tanks have SE MH's.

[brewercm]

DEs tend to be brighter, matter of opinion I know and maybe has more to do with the reflectors used.
I switched over the other way from alton from SE to DE and like the DE's, just less to choose from and usually about $10 a piece more per bulb.

[Bill S]

What Cliff said. More a matter of preference.