Metal Halides - What is too much?

thearnley

thearnley

Member
I'm currently running an Aqualight Pro with 2x 250 watt halides with actinic PC's. I'm not real happy with the light coverage on the sides of the tank. I'm thinking of re-doing the inside of my canopy with a retro kit of: 2 super actinic VHO's and 4 x 175 watt metal halides spaced to more evenly cover the tank. Even though that is 200 more watts of MH than I have now, will the light penetrate as deep as it is now? Will it be too much? Would it be too much if I went with 2x 250 watts on the inside and 175 watt as the outside lights?

:dunno:

Any input would be appreciated. Thanks.
 
reefer4200

reefer4200

Member
This would depend on what you plan on keeping in your tank....for some coral especially softies this might be to much...at least IME. If your planning to do an SPS dominant tank then this shouldnt be an issue...
 
thearnley

thearnley

Member
I have some nice acro's and monti's right now and plan to expand on that big time. I've got some nice softies that are going to be going to the LFS for some credit - they're taking up some 'high end' real estate that could be better occupied by SPS. That's why I'm worried about light penetration - I don't want to limit my SPS to just the very top of the tank.
 
Frankie

Frankie

Well-Known Member
RS STAFF
Your not going to get the punch to the bottom like you were with the 250's.
I don't think your going to have to much light, the question is, can you keep your tank cool with that many lights over it?
 
mps9506

mps9506

Well-Known Member
Frankie said:
I don't think your going to have to much light, the question is, can you keep your tank cool with that many lights over it?
Click to expand...

Totally agree with this.
I ran 2x250 10k halides over my 40 breeder. My issue was keeping the tank cool and topped off :)

Regarding your spread, what type of reflectors do you have and how are they oriented. You should get very decent spread with 2 bulbs and decent reflectors.

EDIT:
I just noticed you said aqualight pro.... They have pretty dinky reflectors in them, probably why your light spread is not satisfying your needs.
2x250's with decent reflectors, or 2x400 if you want to go with 20k bulbs should be sufficient for a tank with those dimensions IMO...
 
thearnley

thearnley

Member
I'm not too worried about the heat - I run a 1/4 hp Oceanic chiller right now with the 250's and it doesn't run very often - just a few times a day for a short time.

Ya, the Aqualight pro has some very small reflectors - the areas right under the lights seem to do well for my sps but anywhere else, I just don't think it gets enough.

I like the idea of just 2 400w MH (and it would be easier to find a retro kit with that setup - and for less $$) but would they give as good a coverage as 2 250's in the middle and 175w on the ends? I know I could handle the heat and I would probably have to install an ATO rather than doing it manually each day.
 
mps9506

mps9506

Well-Known Member
thearnley said:
I'm not too worried about the heat - I run a 1/4 hp Oceanic chiller right now with the 250's and it doesn't run very often - just a few times a day for a short time.

Ya, the Aqualight pro has some very small reflectors - the areas right under the lights seem to do well for my sps but anywhere else, I just don't think it gets enough.

I like the idea of just 2 400w MH (and it would be easier to find a retro kit with that setup - and for less $$) but would they give as good a coverage as 2 250's in the middle and 175w on the ends? I know I could handle the heat and I would probably have to install an ATO rather than doing it manually each day.
Click to expand...

The coverage is more dependent on the reflectors than anything. 2x400watt setup will let you grow pretty much anything you want top to bottom in that size tank regardless of color temperature.
The light you get towards the sides of the tank will be more dependent on the reflector. going with 400 watters will also allow you to mount your lights higher up off the tanks, and naturally the light will be spread out more by the time it hits the water surface, it won't give you the spot light sensation you are getting now.
 
D

DaveK

Well-Known Member
From what was being said in the original post, it seems the issue is more the light coverage, rather than the amount of light.

I think the idea of four 175w MH would work fine, but the idea kind of falls apart when you consider costs. The equipment for four 175w MH is almost as expensive as 250w equipment, and you'd need to get four ballasts and so on. Since the light patterns would overlap and is slightly higher, you shouldn't have an issue with the light in the system.

The idea of two 400w MHs would also work, but 400w bulbs give you a lot less options in the color temp area.

I would first try raising the fixture about 6" or so as a test, and see if that lights up the ends more toward you liking. If you like it that way, you need do no more. If not, I think your best option might be to see if you could retrofit two 175w bulbs, one at each end, and reposition the 250w bulbs slightly.

You could also add two 250w bulbs as above, and really add a lot more light, but then the nice people at the electric company will send you a much larger bill.

As you can see, all these methods will work. It's simply a question of choosing the method that works best for you. Cost is also a consideration.
 
BigAl07

BigAl07

Administrator
RS STAFF
If I woke up in your shoes *they'd need to be really LARGE shoes though*


I think I would opt for a pair of quality 250W with high-end reflectors. That's going to give you a good balance of power to penetration to spread. Don't get me wrong 400W would easily take care of the penetration but wont really "affect" the spread unless the reflectors are "tweaked". The 400's would just be a LOT of power for that size tank. As Dave pointed out your local electric company may set up a special armed courier to pick up your power payment LOL! Just kidding but not really :)

:D
 
thearnley

thearnley

Member
Well, I made a decision - but I'm not sure it was the right one. I think maybe I should have taken more advice from this thread but we'll see.

I went with 2 110 actinic VHO's with 2 400w coralvue 10k with coralvue ballasts. I'm modifying my canopy so that it will raise the lights to where they are 7-8" from the water surface (24" deep tank) lining the inside with reflective aluminum. After testing one those puppies up and feeling the power (and heat), I'm a bit worried. Am I going to bleach my SPS with too much power? I'm running a 1/4hp chiller and I'm going to add 4 3" fans to the back of the canopy (2 fans blowing in and 2 blowing out) so I'm hoping the heat won't be as big a factor as having that much power so close to the corals. I hope I'm just having a unwarranted panic attack. :eek:
 
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