MH height

[dtaranath]

I currently have a 90gal (24in height). I just received a new retrofit, 2x250W MH with 2x110W VHO. There will be two 4" fans blowing over the water, and there is no chiller.

What are your recommendations for height of the halides above the water line?

I was planning on making them about 8 or 9 inches, but someone had told me that height is not enough. is this true?

[Reeforbust]

Mine are 6" off the water in a close canopy and it heats the tank up 3 degree's through my 10hour MH cycle.

8-9" would be great......

[jasonstr8up]

You should be fine. But you might have a heat problem. I have a chiller. I hooked up my MH's up 3 weeks ago. Now my chiller runs twice as much. I also have (2) 3" fans.

[dtaranath]

i'm hoping to avoid using a chiller.

[Reeforbust]

Are you using a canopy??

[jasonstr8up]

I wish I could do without my chiller. They are very loud, and generate alot of heat.

[jasonstr8up]

Hey Reeforbust,
How high does your temp get?

[dtaranath]

<a href=showthread.php?s=&postid=6490359#post6490359 target=_blank>Originally posted</a> by Reeforbust
Are you using a canopy??


yes, i'm about to build it. that's why I was wondering if I could get away with 8-9 inches on the MH height. the total canopy would be 12 inches in height, and the MH hangs down about 4 inches, thus giving me 8 inches off the water.

[jasonstr8up]

That’s exactly the same dimensions as the canopy I built. 12� high and the lights hang 4� down. That’s all the clearance you need to prevent the bulb from being splashed and having it burst. I think the absolute minimum clearance is 6� from the top of the water.

[Reeforbust]

I made my canopy out of 1x12's (which are actually 3/4"x11 1/2")

With the almost 2" overhang to cover the trim on the aquarium, I ended up with a usable 9" or so which put my lights a lot lower than I wanted. Make sure you have a full 12" above the tank to work with. I always see real tall canopys and never knew why untill I got my MH's........

[Entropy]

I have my halides 3.5 inches off the water, but my tank is in wall so the canopy is completely open on three sides and I have a 9 inch fan cooling the canopy area. The problem with building a really tall canopy is getting your VHO's close enough to the water. In my case the VHO's are at the same height as the halides, so to raise them up really far would also raise the VHO's.

Splashing and heat has not been a factor so far for me.

[jasonstr8up]

I mounted my VHO's on the sides of my canopy. 4" above the water.

[jasonstr8up]

<a href=showthread.php?s=&postid=6490838#post6490838 target=_blank>Originally posted</a> by Entropy
I have my halides 3.5 inches off the water, but my tank is in wall so the canopy is completely open on three sides and I have a 9 inch fan cooling the canopy area. The problem with building a really tall canopy is getting your VHO's close enough to the water. In my case the VHO's are at the same height as the halides, so to raise them up really far would also raise the VHO's.

Splashing and heat has not been a factor so far for me.

:eek: 3.5"? And you don't use a chiller?

[Entropy]

175w versions don't get as hot, and I have a 9 inch fan. Also keep in mind my canopy is completely open (no sides or back) on three sides. I have very good air flow needless to say. I am not sure it would work on a closed canopy or smaller tank.

[fishpimp69]

mine are 1 inch off the water which is crazy i know, but i have been running them this way for 8 months now with no problems. In the winter my water temp stays below 79 but in the summer shoots up to 82-83. But I would like to raise them just haven't had a reason to. If anyone can think of one let me know...

[Entropy]

You might get a little better light spread if you raise them up a bit especially with a good reflector.

[dtaranath]

I guess if I leave them at 8 inches above the water, I could always cool the water a little more (if necessary) by adding a third or fourth fan...

i understand the reason for the tall canopies; I just hate the look of it.

[jasonstr8up]

They don't look that bad. :) Check out Reeforbust gallery his came out really nice... it's without that cheasy look that I have seen around. Mine came out real nice too. Just be creative, don't be afraid to use some molding and onlays. You could end up making a nice pice of furniture.

[Entropy]

You could always put the tank in the wall. :D

[jasonstr8up]

Make sure you don't make the same mistake I did. Before, I had a hood that folded over and it was only 5" high. I designed mine. I thought I figured everything out. I built it, stained it, and wired everything. Well.....I put it on the top of my tank...It looked great.
Everything was perfect... I though... So I went to put my hand in my tank to move a PH.:eek1: I could only put about 6" of my hand in the tank:eek: :mad2: I designed it w/ a flip lid so I had to take the hood off and I cut two rectangles out and used a small piece of molding to frame around the rectangles I cut out. They look like a decretive door panel.

So now I can pop the panel out and access my tank easily.
:cool:

[dtaranath]

<a href=showthread.php?s=&postid=6491920#post6491920 target=_blank>Originally posted</a> by jasonstr8up
They don't look that bad. :) Check out Reeforbust gallery his came out really nice... it's without that cheasy look that I have seen around. Mine came out real nice too. Just be creative, don't be afraid to use some molding and onlays. You could end up making a nice pice of furniture.


Ahhh, yes. I took inspiration from Reeforbust's canopy when I built the canopy for the 30gal I placed in my study (haven't gotten a chance to get it up and running yet). You can see which part of the canopy Reeforbust provided the inspiration for ;) :


http://reefcentral.com/gallery/data/500/101986finishedstudy_016.jpg

http://reefcentral.com/gallery/data/500/101986finishedstudy_020.jpg

http://reefcentral.com/gallery/data/500/101986finishedstudy_026.jpg

(thanks Reeforbust! :D)

And jasonstr8up, your tank is absolutely beautiful. I'd love for my 90 to look like yours one day. Your canopy doesn't look all that tall. Is it really 12" height? Either way, it definitely looks great. Kudos to you.

[Reeforbust]

No problem.......................Looks good!!!;):D