MH lights raising water temp

I just got my new MH bulbs in today and fired them up for the first time and my temp is steadily going up, It started at 79.7 and 4 hours later its 81.9. I dont know how hot it too hot ive heard as high as 86 or 87 would be ok but Im not sure. Any advice is appreciated.

 

86? I don't think so.
I would say 82 is OK, but not desirable. You should have some area in the canopy for the hot air to get out. And then maybe add a fan to get the temp down.

 

i would try to keep it under 80. Yeah a fan would help. how far are ur lights above your water. they should be 8-10". mine are about 10" off the water. My temp is about 76-77 when mine are on.

 

I do have two 4" fans in the hood with an open back and the bulbs are exactly 7inches from the water surface. I have 2 - 250 watt MH bulbs over a 90 gallon. If it gets over 83 I guess ill shut em off...

 

I have the same setup here with the 2 - 250w mh bulbs. I turn them on for 4 hours in the morning and 3 hours in the evening. It helps keep the temperature down (around 81 degrees F), and right now nothing I am keeping requires that much light. I leave the 190 watts of actinics on from 6:30 in the morning to 7:00 at night. I sure can't afford a chiller and would prefer not to use one!
I wonder if a sheet of tempered glass between the bulbs and the tank would minimize some of the heat transfered?

 

I wonder if a sheet of tempered glass between the bulbs and the tank would minimize some of the heat transfered? <--- I was wondering the exact same thing , I guess it wouldnt hurt to try.

 

I have my 175 W metal halide in a canopy with a piece of plexiglass.

1. It keeps the bulbs clean and safe.
2. It keeps some of the heat out of the tank. It gets vented with one fan on one side and just an opening directly opposite the fan.

BUT

glass or plexiglass will cut down on some of the light that actually gets down into the aquarium.

 

[quote author=birdlady link=board=ASAP;num=1100995412;start=0#6 date=11/20/04 at 17:29:59]Iglass or plexiglass will cut down on some of the light that actually gets down into the aquarium.
[/quote]

If you keep the glass cleaned weekly the 250w bulbs should be fine in reaching the bottom of your tank.

 

Wondering if a sheet of tempered glass between the bulbs and the tank would minimize some of the heat transfered?

Great minds think alike
Jim

 

Well the temp got up to 83.5 and probably still rising before I pulled the plug. I raised the hood 1 1/4 Inch higher so the bulb is now 8 1/4 inches from the water surface instead of 7, the hood dosent look as good as it did but... I hope this works , If not I'll add another fan or 2 and if that dosent work a baseball bat should do the trick.