lighting question

[ShawnJones]

I keep seeing different answers to this question, so I thought I would just get my own answer. Here we go. I have rebuilt my tank and am planning to keep coral. The tank is 100 Gallons, 48" long, 24" deep, aprox 25" bulbs to sand. The tank currently has a IceCap 660 running X2 10,000K VHO's, and X2 actinic O3 VHO's. I have done the basic math and that comes out to about 4.8 watts per gallon. I have to say, the lighting is pretty intense. The question is does this seem like enough for coral? If so am I limited to what types? Thanks for everyones help.


Shawn

[jojo22]

At 48" long you might want to try adding 2 MH bulbs at about 250W it would be fairly inexpencive if you could put it all together yourself and would leave you with very few limits.

[fsn77]

What kind of corals do you want to keep? 4 VHOs would be plenty for a wide variety of soft corals and many LPS corals. It wouldn't be good for SPS, though.

The WPG rule really only holds for standard fluorescent lighting. Beyond that, things get more complicated.

[ShawnJones]

Basically the types I am looking at is some zoo's, xenia, and acropora. My main problem with the MH is that I am renting the house I'm in right now. The house was built in 1932 and the electrical is a little old. Trust me it's safe, thats not what I am saying. The way the circuits are arranged are a little unique to say the least. For example, my tank is on an outlet that is on the same circuit as the master bedroom(across the house) I already replaced the service panel because of a tree taking out my service drop and weather mast and have gone under the house and poured new footers under the tank for the weight, and don't feel like helping someone else's property value by updating the electrical any more that necessary, I'm sure you all understand.

What I am confused about is this. (example) if I have 440 watts of VHO @ 10,000K and that puts me in the limits for watts/pg, why would 440 watts of MH @ 10,000K be better? I do notice that the MH seem to have a more focused pattern in the water, is this the difference we are discussing here? I just want to be clear on the reasons for doing this. Thanks for the input.

Shawn

[jojo22]

Metal halides penetrate the water colum better. so basicly you could have less wattage and get more "useable" light to your corals. Take me for example. I just switched my nano from a 96 watt pc 50/50 to a 70 watt 1400K halide. This was about 4 days ago. my corals already have better polyp extenxion and are generally healthier looking (not color just general apperance). this is because they are getting more PAR or light of the proper spectrum to be used for photosynthisis. That would be the only thing that makes a halide better. that and they give you the pretty shimmer look in your tank and the PAR makes you corals grow a little faster.

[fsn77]

For Xenia and zoos, the VHOs will be fine. Some of the lower light acros might survive at the very top of your tank, but I wouldn't expect much from them with only 4 VHOs.

MH and VHO produce a different amount of PAR (photosynthetically available radiation, or "intensity") per watt. Because of this, X watts of MH does not create the same light conditions as X watts of PC, T5 HO, or VHO lighting. Within lighting types, different bulbs of the same wattage can produce different PAR. A 10,000K bulb usually puts out more PAR than a 14,000K bulb or a 20,000K bulb.

Essentially, watts is nothing more than the energy consumed by the bulb. The difference between lighting types is the efficiency by which the watts are used to create light. MH, generally, creates some of the highest PAR per watt of the common lighting types. The rest fall in line something like this -- T5 HO, VHO, Power Compacts, Normal Fluorescents.

If you feel you need more light, it may be a reasonable upgrade to keep the IceCap 660 and use it to run T5 HO lamps with individual reflectors. Running T5 HO on an IC ballast is commonly called overdriving. It's safe when done properly (like any other DIY project), but does create more heat and does require some sort of cooling for the bulbs to keep them running optimally. Overdriving T5 HO bulbs does shorten their lifespan some, but they'll still go 12 months or more without needing to be replaced. Individual reflectors run about $20 a piece for the 4'-ers, the bulbs average out near $20 each, and endcaps / mounts can easily be found for $12 - $15 or less a pair (perhaps cheaper if you shop around).

[jojo22]

I concur with the coral suggestion and the fact that a t-5 upgrade would be better than what you have and not as expencive as MH.

[ShawnJones]

Thanks for the advice everyone, since I'm not in the position for halides yet, I think that I will stick with the zoos and other low light corals. Crawl then walk then run right? As always, thanks for the help.

Shawn

[NicR]

t5 hos have been great to me on my reefs i have montiporas thriving along with a few acro species im planning on using them on my 90 MH are great and i only recomend them if you want a chiller or have a deep tank