Switching from MH to T5?

[spreerider]

i read a study somewhere and when they tested different mh lights and ballasts most used huge ammounts of energy when starting up and while running,electronic ballasts ran at proper levels but i dont think the starting up was any better,im thinking of buying a kill-a-watt so i can test things myself and know for shure instead of just guessing all the time.
i have no proof myself but i would shure assume any mh light system is gonna use a heck of alot more power than a t5 of similar wattage

watts is a measure of power so there is no way 100w of mh could be more than 100w of T5... 100w is 100w of power, and yes there is a surge of power when a coil and core ballast is first turned on but its only for a very short time and wont increase your overall power consumption noticibly as it only lasts a fraction of a second.
a kilo watt meter wont show you a startup spike a sits too fast to see, you can make your own wattmeter with 2 multi meters by attaching a ammeter in series with the ballast and a voltmeter in parallel then multiply the values together gives you watts
Amps X Volts = Watts.

[midgetwaiter]

Originally Posted by spreerider

watts is a measure of power so there is no way 100w of mh could be more than 100w of T5... 100w is 100w of power

Sort of true. Most magnetic ballasts have a pretty awful efficiency factor and will end up drawing as much as 20% more power than they are rated at in normal use.

[i have crabs]

book i was readin said tar type ballasts use 20-30% more while electronic are almost perfect

[kwirky]

using that 48" fixture on your 60" tank will give you a lot of shadow on the sides but it's dooable. There's a guy on RC that tested T5's with a PAR meter going all the way down his 24" tank. Someone else compared his results to another person's test of 250W MH 10k lighting at 24" and the T5's were about 10-20% brighter. That was with a fixture running 50% 10k's, 25% 14k's and 25% actinics.

With T5 you open up the flourescing ballgame though. Anyone seen those flourescent tanks? they look pretty cool .

As for the electronic vs. tar ballast debate, a 250W electronic ballast will draw only 250W while the TAR will draw like 300W. the TAR ballast will output 300W of light however, while the electronic outputs 250W.

Some people go the whole mile and pair specific bulbs with specific ballasts because you'll get different colour temperatures out of them. Especially for the 400W bulbs.

[midgetwaiter]

Originally Posted by kwirky

As for the electronic vs. tar ballast debate, a 250W electronic ballast will draw only 250W while the TAR will draw like 300W. the TAR ballast will output 300W of light however, while the electronic outputs 250W.

You certainly get more PPFD out of an HQI ballast but that doesn't always hold true for standard magnetic, especially with 10k bulbs.

Originally Posted by kwirky

Some people go the whole mile and pair specific bulbs with specific ballasts because you'll get different colour temperatures out of them. Especially for the 400W bulbs.

PPFD varies considerably as well in some cases.

[fkshiu]

Originally Posted by i have crabs

book i was readin said tar type ballasts use 20-30% more while electronic are almost perfect

Here's a comparison of how a single type of bulb (Phoenix 250W SE 10K) does on various ballasts:

http://www.reeflightinginfo.arvixe.c...&Submit=Search

Note that the electronic ballasts use pretty much their "as advertised" wattage (power column). Compare this to the increased power usage of the magnetic/TAR and HQI ballasts, but at the same time you get more useable light (PPFD column). Note also how colour (CCT column) varies according to which ballast the lamp is on even amongst the three electronic ballasts.

The same concept holds true for T5s. An Icecap 660 ballast will overdrive a 54W T5HO lamp to about 80W and an increased amount of light will be realized, but at the expense of somewhat shortened bulb life if you don't employ proper cooling. In contrast a Workhorse ballast won't overdrive, but you'll end up with less light.

However, this lowered bulb life expectancy does not occur with HQI/TAR ballasts in MH as you might expect IME.

In the end, you must choose your bulb/ballast/reflector combination carefully according to your own needs and tastes. I suggest that you look at as many other tanks as possible before settling on a particular system. It's usually a trade-off between looks and growth.