Metal halide and colour temps

AquaticJim

Guru Class Expert
Aug 2, 2007
173
0
16
Just wondering what most people are running that use MH.

What colour temp are your metal halide lamps and what wattage are they?
 

Gerryd

Plant Guru Team
Lifetime Member
Sep 23, 2007
5,623
22
38
South Florida
Kelvin

I have a 72" Current Outer Orbit using 3 150 watt 14K bulbs on a 180 gallon tank. Lights are suspended 15" above the tank. Also, I have a dense cover of duckweed.

Lights are very bright, hence the duckweed.

I have grown many types of plants and have not had any issues with any of them.

I will say that the effect is different, but not unpleasant. Nice ripple effects on the water. I have mostly Cryptocoryne species and they do very well, and have even flowered on occasion.

One bad thing, is that ALL of my driftwood gets covered in a dark green brush algae. Looks nice so I don't mind. Every 7-10 days, I just use my fingers to remove excess as it does grow quickly.

Does NOT affect the plants or anywhere else, just the driftwood.

I am thinking of switching to 6500K bulbs.

On: 9:00 am
Off: 3:00 pm
On: 6:00 pm
Off: 12:00 midnight
Total Photoperiod: 12.0 hours
 

tcomfort

Junior Poster
Jul 24, 2007
26
0
1
54
Littleton CO
I use Coralife 175 watt pendants. I have always used the 6500K bulbs, but I am considering trying the 10,000K bulbs that are everywhere now. I kind of like the bluer look (as compared to the yellowish cast of the 6500K), but I haven't tried them yet.
 

FacePlanted

Guru Class Expert
Jul 9, 2007
115
0
16
44
Austin, TX
I have a current outer orbit 24" fixture with 2-65watt CF bulbs(6500K) and 1-150watt MH bulb(10000K). It is raised about 3ft. above the water, as it is over a 29gal tank. I love the ripple effect from the MH, and the intensity is great, even at this distance above the water. The MH really brightens up the colors of the tank, and casts shadows on the substrate. If the bulbs get old, or I need more light/intensity, I can just lower the fixture as needed.

-Mike B-
 

Gerryd

Plant Guru Team
Lifetime Member
Sep 23, 2007
5,623
22
38
South Florida
6500k Switch?

Hi Tom,

Do you then reccommend that I switch from 14k to 6500k?

I am happy with the look and growth of my tank and don't want to change just for change's sake. However, everything I have read over the years indicates that the lower the kelvin the better red/yellow spectrum which plants like best.

I have seem some debate over this on previous threads but never seem to see a definite conclusion, unless I just missed it (a distinct possibility).


On another note:

I have seen many threads now where you talk about the plumbing and setup of the 350 gallon and refer to more detailed text, but have not been able to find it.'

I want to investigate your suggestion to me (and others) on converting half of a overflow type reef tank to a canister filter. Also, since this large tank has a sump and trickle filter (I think?) this is similar to my setup, so am especially interested in how you do it.

I am absorbing a lot of info lately here and am thinking about a change to my setup as I really admire the tanks I have seen here.

Great site and thanks for all the information!
 

Crazy Loaches

Guru Class Expert
Nov 20, 2006
103
0
16
Ohio
Gerryd;19590 said:
I have seem some debate over this on previous threads but never seem to see a definite conclusion, unless I just missed it (a distinct possibility).

I think you wont find a definite conclusion about color temp because the bulbs vary widely. I've not used MH so I dont have any experience but in my research (I contemplated using them but to pricey) mostly from Sanjay Joshi's testing, showed that the tested color temperature was often much less than the K rating the bulb was labeled. Also, just because it has a high K rating doesnt always mean it has less red for example, just more blues. As I recal the Iwasaki 15,000K bulb had one of the highest amounts of red in it compared to all the rest of the similar wattage bulbs tested - however there werent too many lower-K bulbs tested since it was for saltwater use.