Halide questions

[Spyder]

OK so stumbled into three 25w MH ballasts and Im' just not sure if I can put one over my tank and it be effective or if I should just wait till I get a different tank?

Here is the deal; my tank is 30" wide, 20" from the waters' surface to the sand, now here is where my concern lies, there is a 1 1/2" brace in the middle of the tank.
I also got two DIY copies of lumenarc reflectors (23 1/2" x 10 1/2")

So my questions are will the brace block too much light, melt, get brittle and crack?
I have seen that I need UV filtering glass. Where can I get this stuff, is it expensive?

Well thats it for now but I might have more questions later.

 

[Spyder]

Just a lil bump

 

[RBursek]

Was that 25w or 250w ballast? You would only need 2 MH at 250w for your tank. The glass is used because SE MH can burst and the glasss lens prefents the glass getting into the tank, I believe it has nothing to do with UV rays.

 

[Spyder]

It was supposed to be 250w (I'll fix that)
2 250w halides for a 30 gallon tank????
Why do you say that? Is it because of the brace?

 

[AZDesertRat]

I think a single bulb with a good reflector would suffice on a 30" tank with good coverage. The reflector will eliminate any blind spot or shadowing the center brace would cause. You might need to play with the correct mounting height to get best coverage at first.
If the bulb is say 9" or higher above the plastic brace it should not get hot enough to cause problems.

 

[mizzo]

Its my understanding that all glass will provide the UV block needed for DE bulbs. Just don't run them without a glass shield.

 

[AZDesertRat]

That is true but its best to have tempered or high heat glass, I broke a few pieces of Home Depot glass on my old DE pendant before getting a better piece cut at a glass shop. SE bulbs do not need a glass shield since the outer part of the bulb is the UV shield.

 

[Spyder]

Thanks guys. I appreciate all the input, and I learned something new. I didn't know that SE bulbs don't need a shield, that is what I will be using when I get it set up.

How much heat will this put into my tank?
I have four 3" fans, will they be enough to keep the tank cool if I built them into a hood?

 

[Spyder]

These are the fans that I have. They have been laying around taking up room for a few years now.
Metal Halide Aquarium Chiller Cooling Fan (4 fan) - eBay (item 330426340169 end time May-01-10 17:30:44 PDT)

 

[AZDesertRat]

I have 2x250wMH and 2x140w VHO in a completely enclosed canopy with only two 4" computer fans for cooling, one in each end, both blowing in and exit holes in the roof of the canopy. I'm in Phoenix, keep my house warm while we are at work and they do such a good joib I sold my 1/4HP chiller. Thye are Vantec Stealths and powered with a variable voltage DC power suply so I can speed them up or slow them down according to the seasons and cooling needs.

 

[LPAJ5280]

2x250w metal halides is overkill, but if you can keep your water temp low (78-ish) your coral will explode with growth. I would recomend a chiller if you have a canopy. That water could heat up like crazy with 2 MH's. Here at the university we had a chiller go out on a 150 and the water got to 91.5. we have 3x250w MH's and they're in a canopy but all in an air conditioned building. My recomendation - get a chiller, get great fans or don't have a canopy.

 

[AZDesertRat]

Fans work fine if and thats a big IF, configured correctly. My system is proof of that.After two seasons of the chiller not running I sold it and thats in Phoenix with a house cooled only by evaporative cooler in the shoulder months and a heat pump with setback thermostat set at 80+ when we are not at home in summer months. Tanks stays 79-81 with no effort year round.