HQI vs. Mogul

HL649 · #1 10-15-2009, 12:30 AM

Yes, it is the common 21" deep 75 gallon. I have considered T5's but always come back to the MH systems. After reading the comments here I am starting to lean towards a 175w SE system with a couple of T5's running actinic (I like to run the actinics 1 hour at dawn and dusk). I will most likely have nothing but LPS and softies as I like the motion of the corals in the flow. Might try the odd SPS but nothing serious. I seem to be liking the SE over the DE bulbs. I am screwed up here or not?

BlueAbyss · #2 10-15-2009, 12:53 AM

To answer your earlier question, there are people who overdrive their MH bulbs... I've heard of running a 150W DE bulb on a 175W ballast. Many electronic ballasts can 'sense' the bulb it's connected to, and will run the appropriate amount of power ie: a 175W electronic ballast will run a 150W bulb at 150W. I don't think this goes for all electronic ballasts, however, and overdriving your bulbs will reduce their life.

I would definitely go no less than 150W with that depth of tank, if you aren't planning anything beyond LPS and softies that should be enough (though PAR values may be a little low at the sandbed). Remember also that just because there are 25 extra watts at the bulb (from a 150W DE) doesn't necessarily mean that you will get that much more light out of your system, this has more to do with the bulb and ballast combination than anything... a 150W 10K bulb on the appropriate ballast could easily produce more PAR than a 175W 20K bulb on a magnetic ballast, though the same may not be true of that same 20K bulb on an electronic ballast.

I went through the same thing when I started my tank... I was originally going to go with T5s.

Eyford01 · #3 10-15-2009, 01:00 AM

umm if it helps i have a 55g tank about 20" deep and use one 250W 14000k single end bulb on a probe start ballast and everything seems very happy from my zoas and shrooms up to my squamosa montis and digitata and everything in between i know very little about light just that this one seems to work for me!

Gizmo · #4 10-15-2009, 03:03 PM

HL649, I Ran 2 250w XM 20k Mogul Bulbs on my 75G. I build my own xfmr using a probe start ballast. Worked like a damn. I still use the XM20k on my SPS tank and they grow well under that light.

kien · #5 10-15-2009, 03:31 PM

If need be, you could always raise the lights from the top of the tank. That's what I had to do. It can be a bit of trial and error.. My current tank is 20" deep and my lights (250w 14K DE HQI) sit about 12 inches off the water's surface. That height seems to be just right for my SPS that are on rock work and my LPS'/zoos that are on the sandbed. I like the added bonus of having virtually no salt creep on my lights which I always hated when I had my lights lower. I haven't really heard from anyone who was overly disappointed with either light technology.

Myka · #6 10-17-2009, 08:14 PM

I'm a total halide fanatic, but I wouldn't run halides on an LPS tank. Too much light, plus you pay only a little less for a 150w or 175w halide bulb as you do for the higher wattages, so it just seems a waste. If I decided to make my tank LPS dominant again I would sell my halides and get T5s. I had an LPS tank recently that ran very well for 2 1/2 years with T5s. Most people would be surprised how little light LPS need in order to thrive. Many people over light them, and when they cut back lighting they experience much brighter colors. Besides, the T5 bulb choices give you lots of options for "color cheating".

StirCrazy · #7 10-18-2009, 08:07 PM

Quote:

Originally Posted by Myka

I'm a total halide fanatic, but I wouldn't run halides on an LPS tank. Too much light, plus you pay only a little less for a 150w or 175w halide bulb as you do for the higher wattages, so it just seems a waste. If I decided to make my tank LPS dominant again I would sell my halides and get T5s. I had an LPS tank recently that ran very well for 2 1/2 years with T5s. Most people would be surprised how little light LPS need in order to thrive. Many people over light them, and when they cut back lighting they experience much brighter colors. Besides, the T5 bulb choices give you lots of options for "color cheating".

this is kind of a grey area, MH is not to much light for LPS, but if you were using T5's for a long time they will take a while to adjust. look at the reef around austrailia and haiwii, there are LPS in 5 feet of water which are reciving more PAR than we could ever dream of putting in our tanks. the problem is most people don't have enough flow in there tanks to prevent/minimize bleaching. I have done exparaments after reading a few articles on bleaching and water flow and which a low flow rate of 20X turnover I could bleach the heck out of frags, but when I increased the flowrate to 120X I couldn't get them to bleach at all with all other conditions being the same.

now just increading pumps isn't enough, the trick is to spread the flow out all over so it ends up being a gentle current not a jet wash, I had a 94 gal tank with almost 12000 gph flowing in the display, but you could put your hand anywhere and all you felt was a gentle flow.. it took me about a week of screwing around with placment and such and I don't think you would ever acheive this with a sand bed (as the flow on the bottom of my tank was the same as the middle and the top) and you may have to be willing to rearange your rock to give you the best flow not the best look, but you could probable achieve both with a little more paitents than I have

Steve