Switching from MH to T5?
 

I've been thinking of switching over to HO T5 from my MH set up. Currently I have 2 pendant style 250 watt MH lights. The T5 setup I would switch would be 48in long (tank is 60in) and six 54 watt bulbs. I would change two of them to blue or purple. My tank is a mixed reef, has anyone switched over to T5 for MH? And what was your experience like? Any info on T5's with a mixed reef would be great.

Thanks

If you do make the switch, let me know, cuz I may be interested in your MH's. :razz:

Am I remembering correctly, your tank is 30" deep?

Hi Doug,

Yes that's right the tank is 30 inches deep. At the moment the SPS that I have is placed higher up and is growing pretty good. Anemone's and LPS are lower down.

Thats a pretty deep tank for T5s. Not sure what the par readings are with T5s on a 30" deep tank, but if it were me ,I would go with a 8(or more) bulb light. Why are you wanting to switch? Your canopy is big enough that you could easily retrofit in some T5s to get the color your looking for.

i switched from 2x 150w mh to a 8 bulb t5 tek light on my coral tank wich is 28" deep i noticed a huge difference in brightness but im not shure if the jump in par was quite as dramatic since i havnt noticed and difference in my corals really,im thinking of eventually switching to 3x250w with some t5 aninics when i have the extra money since i miss the rippiling look already

Well I was thinking of switching to the T5's to even out the light distribution over the tank. With the MH pendents I have the middle gets less light. I also wanted to use less energy and reduce the amount of heat going into the tank.

There was a poll a bit back (here), might have some helpful comments

Mike, I haven't ever actually used MH, but I do currently have an 8-bulb Tek unit over my 3-foot tank. I love it! I'm keeping soft corals, LPS, SPS, a Gigantea anemone and a clam...and all seem to be quite healthy and happy. You're free to come over and see if you want. I'm using a mixture of bulbs and really love the colours.

how many watts is a 8 tube tek in total, compared to your 500W now?
thats how much power it uses doesnt matter that its MH, incandescent or T5.
432 is a 8 bulb tek if i remember correctly, so thats not much savings in electrical energy, probably wont pay for the upgrade costs for at least a number of years.
But i would go with what you want your tank to look like, i personaly love the shimmer for MH and would never go with anything else, I also like that there are darker parts to put lower light coral in to give more contrast in my tank. But it sounds like you want even consistant lighting, so go with the tek its your money spend it how you want :)

Have you considered putting a couple fans in the canopy?

Yeah I thought about that. I'm more interested in even light distribution and if I used a 6 bulb 54 watt T5 setup it might be worth it on power savings but maybe 6 bulbs wouldn't be enough.

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

Mike, how wide is your tank? Could you get an 8-bulb unit?

i say add a 3rd 250w with some t5s aninics or fji purples if thier is room.
if i had a 24" tall tank or shorter i think id keep the t5's i bought but im not satisfied with what i see from my corals, it would be good if someone had a lux meter and a par meter so we could test a bunch of set ups and actually have some numbers to judge things from instead of the same old argument.
i know i have other things to spend $500 on right now though,

heres a lilttle read about par even though its just about mh's

The tank is 24 in wide. I've thought about adding a third pendent in the middle. It would be nice to get rid of those super hot ballasts in my stand rather than add another one though. Maybe I should save up and buy a MH T5 combo unit. I'm due to buy new bulbs for my current set up and I need a new capacitor for one of the ballasts so I figured if I was going to make the change now is the time.

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.

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.

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

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.

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.

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

PPFD varies considerably as well in some cases.