Metal Halide Set up.............?

Question

I've been reading on these light systems on the net, I was wondering if you guys have any pointers for me to consider if I overlooked.
I have a 125Gal Bow front Tank, it's about 2ft deep, and 4 ft wide. I am building a hood for it, and I want to use a 250 or a 400 watt 20,000K Bulb.
How far should I mount it from the water surface?
Also, any warning you can give me would be greatly appreciated...........

I can reduce the wattage, that's no problem, I know about the fans, I'm going to install those, I'm really concerned about the last post about easing them in with the light..........Where can you buy a good set of timers?

Answer 1

For balance you should add a couple of tubes that come on before the main lights and go off after the main lights, you don't really want the full day sun suddenly appearing.
I would sit and look at the tank and try and gauge how high they're going as you don't want the full glare coming at you as you sit and watch TV, however you want them high enough from the top of the tank so you have easy access, as others have pointed out they're very hot, and if you stare at them they can damage your eyesight (I know if your daft enough), so maybe think about putting side panels to drop further down to direct the light. Of course because of the heat you do need fans as others have said.

I started with pendents which is why you don't tend to think about what you can see when your sat down. Then moved to a suspended hood type which I placed about 2 foot above running with 4, T5 tubes which came on 2 tubes then 5 Min's later the other 2 tubes then 30min the main lights, and the tubes then went off, and came on just before the main lights
went out in reverse order.

As some one said the size of bulb your talking about maybe a little big for the tank I had 20k on my 6ft.

But to put it all into context I'm running this tank now with the 4 T5's with just as much success with the plants.

AJ

I used something called system 2000 which has a central box for power, which can drive what you like but has really no control filters went on this then, connected to that I had there light box which gave me two sockets with independent timers, (so i had two of those), they also controlled the CO2 system so when the lights went off the CO2 stopped, the second one controlled the main lights and the air pump which came on once the lights we're off.
Another box which controlled the heating with undergravel cable and 2 heaters.

While I was disgruntled when i first bought the system I've had it over 12yrs now and the first piece has just gone wrong, so for something that is operating 24/7 its served its purpose well, mind you each box was about £100 there or there abouts. So not a cheap option, but all tucked away in the cabinet.

Answer 2

Get it at least 12 inches off the surface and have plenty of fans for circulation. They run wicked hot. Also, for a 2 foot deep tank, 2 X 175 watt halides are more than adequate; 250 or 400 watts are just overkill and might actually be too much for some of your corals.

Answer 3

12" is good, 2-4 fans, half blowing in and half out are a good option too on the 175's. the heat may still be quite a bit, a chiller may be required, DIY plans exist for thm as well. placing them on a timer is agood idea. if you have a deep sand bed or dont plan on adding any SPS or clams you could go down to a 150w, i prefer the HQI bulbs over screw in, but thats me, if you do plan on them disregard my last comment lol use a month or less to slowly acclimate the corals you do have to the new lighting, start with 3-4 hours and builkt up slowly to 8 hours a day. a good reflector can to alot too. if you do wiht the 250's (400 are way over kill even for acros) you will need a chiller and you may still need one, oh and use 2 bulbs. with a 20000k you wont get alot of fast growth out of the corals, going with a lower kelvin and adding t-5 actinics (space) would work too, just me 10-14k is as blue as i like, but now im just being rude lol

Answer 4

Hi, I would also put include a small fan. So that your light doesn't over heat. You should keep the light about 12 inches from the top of the tank. Also make should you ground it well. Other wise it could be a very shocking experience for you and your fish.