building canopy for 75-90g need advice on MH

krazekajin

krazekajin

Active Member
I am getting everything together to put a 75g or 90g tank together. I am going to do a predominently SPS tank so I am trying to get everything together. Right now I am only waiting on the tank. I have the stand built, a 55g sump/refuge, pumps, Protein Skimmer, etc.
Here is my question. I was able to get three 400w ballasts that I am thinking about using.
Would running one or two on this tank be over kill. I am going to ventilate like crazy with fans and vents so hopefully I will not need a chiller, but I might have to play around with that.
Could anybody give me some advice on how tall my canopy should be if I choose to go with 400w Mogul socket MH?
 
thegrog

thegrog

Active Member
One 400w MH light will not cover enough area, three would be overkill. If going that route, then go with two. Each one can effectively cover a 2' x 2' area.
With that much wattage, you will definately need lots of ventilation.
I would also go with the 90 gallon tank as 800W of MH would be a tad much on a 75 IMO. Plus more water volume = greater tank stability.
For height, 10-12 inches above water surface is where you want the bulbs at. I would go more towards the 12 inch range if I were you.
hope this helps!
 
krazekajin

krazekajin

Active Member
Thank you.
If you were in my shoes, what would you do? Would you try and use the ballasts or would you spend a lot more money and buy 250s or even a bank of 8 t5s?
 
maingo

maingo

Member
I have 2x250w 14k MH retro in my DIY hood, and I would have to say its perfect for a 90. 800w over a 75-90 just seems alittle over powering you might melt anything you put in there the tank itself is only 24" deep 400's are more for those 150 deep tanks and such.
 
thegrog

thegrog

Active Member
Originally Posted by KrazeKajin
Thank you.
If you were in my shoes, what would you do? Would you try and use the ballasts or would you spend a lot more money and buy 250s or even a bank of 8 t5s?
If in your shoes, I would try the two 400W ballasts. Keep them higher off the water surface. Go with 15,000 or 20,000K bulbs (no actinics needed). That is just me being tight with money.
If you want to be sure, then spend some more money and get the 250's and sell the 400's to make up the difference.
OR, just get a bigger tank!!!!
 
krazekajin

krazekajin

Active Member
Grog,
That is very similar to what I want to do.
I was at the LFS and weighing out tank options again. I found that i can get a 90g with two corner overflows. I think I like that option because I want an SPS tank. Thus, I think the 400w will work. I can't really sell the 400w right now, because they do not have all of the parts. However, I think that I could trade or sell them once I get them up and running.
Thus if I get the 400w up and running but they are too hot, etc, then I can sell/trade working 400w lights.
 
bigred

bigred

Member
I ran 400s on a 25" deep tank and they were just fine. The main thing is heat factor. These bulbs throw out a lot more heat then a 250.
 
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