metal halide question

reefiness

reefiness

Active Member
Im thinking of getting metal halides for my 90 gallon reef. I was thinking of getting 2-250watt hqi mini pendents connected to 1 dual 250 watt pfo ballast. the lights would both be about 15000k along with 4 65 watt pc actinics. does that sound like a good set up color wise?
how hot does the ballast get? if put on a wood surface will it set a fire?
also about how much hotter will this light make my tank?
 
golfish

golfish

Active Member
Originally Posted by reefiness
Im thinking of getting metal halides for my 90 gallon reef. I was thinking of getting 2-250watt hqi mini pendents connected to 1 dual 250 watt pfo ballast. the lights would both be about 15000k along with 4 65 watt pc actinics. does that sound like a good set up color wise?
how hot does the ballast get? if put on a wood surface will it set a fire?

I'd do either 10K's if your going to run that much actinics or go with the Phoenix 14K's and forget the PC's....
I'd set the ballast on a couple bricks just to be safe. I've used that ballast (the 400 watter too) its probably not going to start a fire but I think bricks are a better choice.
Originally Posted by reefiness
also about how much hotter will this light make my tank?
That's going to be hard to answer. What are you using now? I'd say if you go open top, hang the pendants above the tank, keep the room cool and well ventilated you probably wont need a chiller.
 
reefiness

reefiness

Active Member
ya thats what im trying to avoid ... a chiller right now i have a 260watt orbit fixture with 2 65 watt 10k and 2 65 watt 420 nm. i also have the versa top on it.
for the halides i was thinking of building them into a custom hood because i dont want to hang them.... i was going to have them like 8 inches from the water and i was going to have 2 fans coming from the sides blowing in and then im gona make like slides on the top so that the air going in will take the heat out the top.
 
golfish

golfish

Active Member
From my own experience I'd say your going to have heat issues. There's just too many factors to say your going to need a chiller or not need a chiller. If it were me I'd can the hoodcanopy and hang the pendants over the tank. You could also make the hood and hang that over the tank. If your going to stick with your idea make the back of the hood open.
 
reefiness

reefiness

Active Member
ok well now that u mention that i guess try to make a shallow hood and hang it because i have to connect the pcs and mh. also the top of the tank would be covered or not? if not will the fish in there jump out? ok another big question how much evaporation will i have and how would i handle that. can i just get like mabye a very small r/o and just leave it on in the tank?
 
murph145

murph145

Active Member
if u plan on putting those lights under a hood at all your going to have heat issues for sure...
i have 2 - 250W DE 20K HQI bulbs and pendants along with about another 180W of 10K PC lighting under my canopy and i have 4 3" CPU fans built into the sides of the canopy and i still run a chiller thats set at 82 otherwise my tank would melt lol....
as far as open tank top.... most reefers run open top because when u start running brighter lights the heat will trap in the tank with no way to vent from the water if u have a closed glass top oin the tank.... open top allows the heat to lift from the water and for evaporation to occur which is one way to disperse heat... as far as evaporation issues i have an auto top off system and i notice that it refills about a gallon to a gallon and a half a day of fresh RO/DI water
once u plunge into MH lighting ur pretty much stuck getting a chiller and a top off system of some sort because topping off yourself gets tiresome
 
golfish

golfish

Active Member
If you put a cover over the tank your going to need a chiller for sure unless you use something like eggcrate. I've had a few jumpers in the past 23 years but not many. I don't worry too much about it. The flow rate might have more effect on evaporation then the lights. I do about 6000 gph through my 120, I have 2x400 watt MH's and probably evap about 4-5 gals a day...
I'd do a search on this site for "Auto top off"
Remember, evaporation is a good thing.
 
reefiness

reefiness

Active Member
i did a google search and didnt find much about the auto top off. if anyone knows any good ones can you give me a brand so i can look it up.
 
cowfishrule

cowfishrule

Active Member
i suggest putting one of the fans on the top of your canopy. remember, heat rises. rather than try to pull it out sideways, pull right out the top. the reflector can get hot, so this helps.
 
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