Evil Side of Metal Halide--NEED HELP!

Hey Everyone...

(I've included pictures to help describe my situation)...
The bottom line is this... I recently added 2 x 150 watt 14k MH lighting with 2 x 54 watt T5HO inside a unit. It sits 5" above the 72 gallon tank on legs inside a half-opened canopy. (fire danger--this is not) The back is completely open, the bow-front top is open and the area above the unit is wide open. Since adding the lights... my chiller has been working overtime. I have the temperature set at 75 with a 3 degree differential. It clicks on every 10 minutes. Now, the unit has two intake fans that blow inside and push hot air through vents at the top of the unit which than gets tossed around with a ceiling fan.

My chiller picks up water from the sump... and then dumps it back into the sump where another pump in the area brings it to the DT.

Should I add two or three fans to the back of the tank to suck hot air out from underneath the lights... I have about 5 inches from the back of the tank to the wall... or should I cut two holes on the sides of my canopy to suck the air out? If yes, which method and which fans are good choices?
If not, what suggestions to help out ... I DO NOT WANT TO BLOW AIR OVER THE WATER BECAUSE OF MASSIVE EVAPORATION.

Thanks for the help!
Ryan
PS I love my new metal halides... but hate the heat! (evil things)
PSS wife says I must keep the partial plastic canopy for looks purposes
PSS how does the tank look in the main picture! ;-)

 

Me personally, I have my chillers running the water into the tank and not the sump. I am surprised the chiller dont run all the time. And I have mine set at 80 degrees not 75. I dont think there is any reason to run a tank that cold. I have a canopy also and I just prop the top open a few inches to let the hot air rise out.

 

If I have a return pump in the sump...
Can I run the water from the chiller into the tank as well? (double -return)

 

I read somewhere that you should have a couple fans blowing OUT.

 

My chiller pump is in the sump. I just put it's return to the return pump's suction so it does not recirculate in the sump. I kept my tank at 77 and my cller ran all the time. I bumped it up to 80 and now don't run it. (For other reasons too). Your tank definitely does not need to be 75.

Try to exhaust as much air as possible out of your canopy. More fans if need be. But air flow is air flow, you will evaporate more. I recently lost another .5 degrees by moving my light up about 3 inches.

Is it possible to ditch the canopy temporarily just to see how it goes. You did say the lights are on legs. That would give you a good idea of the best it can get.

 

I did too... that's why I'm curious whether I should put two on the sides by cutting holes in the canopy (don't want to do that) or would I be okay putting them in the back... even with the wall about 5 to 6" away

* my pictures in original post show all the current canopy openings *

 

Well the chiller is set at 75... but in reality... the DT is more like 77 degrees.
The lights are on 5" legs and can't be changed...
Wife would NEVER allow me to take canopy off... but as the picture shows... the whole back is open... entire top (minus the 12 inches width of unit) bow front open as well.

 

what size tank and chiller do you have? I wouldnt add fans with a chiller. You may as well use that power to run the chiller and keep it simple.

 

tank is 72 gallons...
Chiller is 1//6 coral life
The fans would not be used to cool tank over surface... rather to draw out heat from under MH... (trying to figure out if I can put two fans in the back where the wall is 5" away and get away with out cutting a stainless steel lined canopy for side exhaust

 

Heat rises for sure. put vents in top to help air flow up.