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2-250 mH or 2-400 mH on a 75g?


PeTe PoLyP

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I am not very educated when it comes to halides. I currently have a 20 show tank, for softies and lps. Also i have a 75 gal thats not being used. I would like to turn the 75 into a hard only tank (mostly sps). The tank has a slab of glass over the top, the same thickness as the sides (1/4"). Its about a foot wide directly in the middle. From what i have read here, everyone seems to think that more light the better. But, would 2-400's be overkill? I would like to use the most intense lighting possible. So i guess this is what my questions are........250 or 400? With 400 do i need a chiller? Would the glass on the top restrict the light? Would i be ok if i placed one light on each side? Should i remove the glass?

 

Any input of information or opinions would be greatly appriciated

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Undertheradar

IMO, get the 250watt DOUBLE ENDED HALIDES, not the mogul base / screw in ones. These often have just as much light output as 400wattSE (single ended) bulbs. The glass will restrict the light, but not by enough to make a big deal out of it, unless it starts to get dirty with salt buildup and the like.

 

As far as the chiller, it will just depend. Do you have central air? How big will the total sytem's volume be? Are there going to be other lights, like actinics, as well? etc. The only way to know for sure is to test it out...maybe with freshwater before stocking it...under the worst possible conditions (ie, if close the room off and run a space heater to simulate the heat of summer if that would be a possibility down the road).

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Cellenzweig

I agree with going with the DE bulbs. A 150w DE puts out the light of a 250w SE. I do however think you should remove the glass for two reasons.

 

1) Evaporation will help keep the lighting cool

2) You may have a gas exchange problem if you leave the top on. I don't know of too many people using glass tops on sw tanks. Most seem to use plastic egg-crate it anything.

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ReeferMonkey

You have to use glass on DE halides because they emit UV. SE halide bulbs are coated on the inside of the bulb to block UV rays.

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i was planning on using double ended bulbs, what i was wanting to know is if 250's would be enough.....and you did answer that, as far as the glass, it doesnt cover the entire top, its an oceanic tank so it has the glass midbrace

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OxInYourBox

DON"T remove the glass brace. It's there for structural integrity. I have seen some tanks with the brace removed fail. I'm guessing you knew that but wanted to reiterate not removing it.

 

I think Cellenzweig thought you had a glass cover vs. brace.

 

Unless you DIY or buy used all HQI pendants come with UV filtering glass. I'd keep the brace clean of salt creep and you won't have any issues.

 

I'd go with Dual 250 HQI's as well. Personally I'd go with the Reef Optix III pendants with Ice Cap ballasts. I won't go into color spectrum and actinic supplementation recommendations.

 

As far as a chiller goes you'll have to see how everything goes as undertheradar said. Design your canopy with fans (do a search on RC for muffin (I believe) fans as well as cooling fans. I'm not saying that you won't need one based on your to be setup but planning ahead can save you the $$ of a chiller later if possible.

 

Is the Oceanic reef ready?

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No its empty as of right now.....I have been looking at hello lights for halides for a while. I am having trouble finding an electronic ballast for a double system.....any suggestions?

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oh btw......i thought that it was there for bracing, but i have seen some 75's with the brace removed, Someone told me that if you have a canopy on the tank you dont need the brace..this is the reason i am asking opinions.....i guess i could run through the setup i have been thinking about

 

i am going to build a canopy thats 18" tall, leave the back open, use cabinet doors on the front. I was thinking of putting 2 fans in the top facing out, and one on each side facing in, prob 6" or 8" fans. I will probably go retro with this so i will probably run a sheet of glass under each light, (i dont like the look of pendants on a tank of this size). I planned on using the icecap ballast so it will run cooler. I hope to also get a PFO reflector. I would like to run a 96w Pc actenic 03 as well, i like the blues. I think for the double ended bulb i am going to use the auqua line 10k,(again i like the blue).

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Originally posted by PeTe PoLyP

oh btw......i thought that it was there for bracing, but i have seen some 75's with the brace removed,  Someone told me that if you have a canopy on the tank you dont need the brace..this is the reason i am asking opinions.....i guess i could run through the setup i have been thinking about

 

i am going to build a canopy thats 18" tall, leave the back open, use cabinet doors on the front.  I was thinking of putting 2 fans in the top facing out, and one on each side facing in, prob 6" or 8" fans.  I will probably go retro with this so i will probably run a sheet of glass under each light, (i dont like the look of pendants on a tank of this size).  I planned on using the icecap ballast so it will run cooler.  I hope to also get a PFO reflector.  I would like to run a 96w Pc actenic 03 as well, i like the blues.  I think for the double ended bulb i am going to use the auqua line 10k,(again i like the blue).

 

I'm building an 80gal "Tank Mahal" setup right now and went with 2x250SE Ushio 10k bulbs running off a PFO Dual 250w ballast system. Brand new, the whole thing ran me $377 with a 36" reflector. I could've shopped used here and other reef sites, but I got impatient...

 

Back to the Q-s at hand. I wouldn't take the center brace off unless you're replacing it with two (or so) smaller ones.

 

The temporary hood over my 40L is using the same light setup (minus one bulb) as my soon-to-be 80 and I found that at 12" over the water, the MH light wasn't as strong as the 70w MH setup I just sold. I moved the bulb down to about 8" off the water and the light's MUCH better!

 

FWI understand, with the pendants, you won't need the spider-type reflector. If you're running the SE bulbs, you will.

 

If you're planning on DIY-ing the light setup, there's places that'll sell you just the mounting hardware and DE bulbs for less than the pendants. THEN you'd need some UV-blocking glass between your hood and tank. I'm not sure how you'd make that work under a big reflector... Maybe support the sides of the reflector and screw the glass holding mounts to it?

 

See this reply and the next for pics of my temporary hood. 1x250w SE 10k, 1x96w PC actinic, 1x96w 50/50. The 50/50 is going to be replaced by another actinic as soon as I get around to it... The bottom of the MH light is 8" off the water, the PCs are about half that.

 

Mike

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Cellenzweig
i would go 400w's. the more light the better hands down.

not necessarily, you could end up with some bleaching if you have too much light - and a heat problem as well. If you do want that much light, go with 2x250w DE. This will produce the same light and you'll save the difference in cost after a few hydro bills.

 

Play it safe and run with the brace. They wouldn't have it if they didn't need it.

I disagree. In many circumstances the brace is there simply to facilitate a 2-piece top, making it easier to access the tank. I have cut the brace out of my All-Glass 70g and there isn't any problem. I even checked it with a laser level and there isn't even the slightest amount of bow. Removing the brace is a very common practice on tanks this size. Many 75g tanks (and even larger) don't even have a brace to begin with. However, if it's a glass brace and doesn't cast a shadow, theres no point in removing it. Also- are you sure the glass is only 1/4"? My 70g is a lot thicker - around 7/16". If it's 1/4, I would DEFINATELY leave the brace.

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I don't think bleaching would be a problem, but everything I have read says that the 250W DE bulbs have about the same PAR value as a 400W SE bulb. I have a 250W DE bulb over my 20-Long and I'm very happy. You do, however, have to put a piece of glass between your bulb and your water. Depending on how high the bulbs are, I can't think of any reason not to use a piece of glass, because you could easily break a bulb by simply splashing a little water on it... that would SUCK!!!

 

So, yea, 250W DE is the way to go.

 

-Scott

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As for the brace... why would you want to risk it? Seriously, that is just crazy. Maybe you'll be lucky and it will be okay, but why take the chance? You're planning on using 2 bulbs, right? So the brace will not get in the way.

 

If you must cut it, I have heard of some people doing this:

 

1) Empty the tank...

 

2) Cut a piece of clear acrylic the same size as the brace...

 

3) Using acrylic glue (or whatever the proper technique), connect the clear acrylic to the existing brace at both ends, but not the middle...

 

4) Now, cut away the black plastic/acrylic brace, and you have a clear brace that will not interfere with your lighting.

 

-Scott

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Cellenzweig
As for the brace... why would you want to risk it? Seriously, that is just crazy. Maybe you'll be lucky and it will be okay, but why take the chance?
Wow! There must be a LOT of crazy reefers, since it's a pretty common practice. It's not a risk at all when you have a 70g made out of glass that's about 1/2" thick. It's the same glass that is used on tanks almost twice the volume (sometimes with, sometimes without a brace). I have personally never seen a custom built tank under 100g WITH a brace of ANY kind (standard or euro-bracing), as there is not really a need when the appropriate glass is used. That being said, if you are using 2 lights, cutting out the brace is pointless.
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I broke the brace on my 45T.....came home one day to find my front panel "bowing" out about 1". Scariest damn thing I've ever delt with......drained about 2/3 of the water out and had a new brace FedEx'd. Don't mess with the brace...it is there for structural reasons.

 

A 1"x1" piece of acrylic or glass can hold 100's (if not a 1000) pounds of pressure. Now take a piece 100"x100" and it's only 20-30 pounds. When you add a center brace it greatly strengthens the panel.

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