DE's are still 100w less than a 250. Unless you either overdrive the 150, or use a really bad reflector on the 250 you won't get more light.
(PAR and PPFD are the same measurement)
AB 10k 150DE
Ballast IceCap
Power 172
Voltage 119.7
Current 1.54
PAR 66.9
CCT 12479.3
AB 10k 250DE
[FONT=Times New Roman, Times, serif]
Ballast [/FONT][FONT=Times New Roman, Times, serif]IceCap[/FONT]
[FONT=Times New Roman, Times, serif]
Power [/FONT][FONT=Times New Roman, Times, serif]248[/FONT]
[FONT=Times New Roman, Times, serif]
Input Volts [/FONT][FONT=Times New Roman, Times, serif]120.1[/FONT]
[FONT=Times New Roman, Times, serif]
Input Amp [/FONT][FONT=Times New Roman, Times, serif]2.29[/FONT]
[FONT=Times New Roman, Times, serif]
PPFD [/FONT][FONT=Times New Roman, Times, serif]77.3[/FONT]
[FONT=Times New Roman, Times, serif]
CCT [/FONT][FONT=Times New Roman, Times, serif]7930[/FONT]
So for the same lamp on the same manufacturer ballast you get:
150w you get 66.9 par
250w you get 77.3 par.
it's pretty close for what I do with my lights, and I use 100w less per light. A big saving on the Elec. bill. Now I wouldn't chance 150DE on a 24" deep tank, but I will put them on a 22" tank.
all info from sanjays pages.
B