Metal Halide

[Mekaeel]

what did you pay for that bulb? R950.00?

 

[Warr7207]

what did you pay for that bulb? R950.00?

R 883.85

 

[Mekaeel]

ok not too far,these Geisiman bulbs are damn pricey

 

[Warr7207]

150W MH lamps generally lack sufficient PAR at depths greater than 30cm and then nothing higher than 14k.

HTH.

Dragon, please explain

 

[Mekaeel]

DR means.as the 150W MH's reach below 30cm from the water surface,the lighting isnt as intense as compared to 250W and higher.if you choose 150W make sure its less or around 14K nothing higher

 

[Warr7207]

DR means.as the 150W MH's reach below 30cm from the water surface,the lighting isnt as intense as compared to 250W and higher.if you choose 150W make sure its less or around 14K nothing higher

Meaning it is pure white ?

 

[Mekaeel]

Meaning it is pure white ?

i would say 10K is pure white
6500K is more on the yellow side close to natural sunlight

 

[Warr7207]

So my white halide is Ok for depth over 600mm ?

 

[Mekaeel]

when you say white.whats the k rating on the bulb?also place the bulb nothing higher than 20cm from water level.i currently have 3 14k MH's over my tank which is 610mm deep.

 

[jacquesb]

Hi Warr - and others.

This is my understanding of the whole lighting "thing":

EVERYTHING has to do with the PAR rating of each globe/lamp (which of course is NOT shown on the boxes). I have only read about this - don't have a light meter - so I don't have personal experience with this.

I believe that at the lower Kelvin ratings, the amount of photosynthetically usuable light available to the corals and their zooxanthellae are much higher (the amount of light that actually makes the photosynthetic cells do their work). At a much higher Kelvin rating, this amount of usuable light becomes far less.

The same seems to be opposite between lower wattage metal halide lamps, and higher wattage metal halide lamps.....

The lower the wattage of metal halide lamps, the lower the PAR (available usable light for the photosynthetic process), the higher the wattage, the higher the par....

Therefor the difference too between Normal Output fluorescents (generally T8's) and High Output (generally T5's) as well...

Hope that my explanation makes sense..

 

[Warr7207]

OK, I have a 800mm cube and running a 150 watt halide. Would you suggest upgrading to 250/400 watt.

Or add another 150 watt ?

My lights are 100mm above water level

 

[jacquesb]

Hi Warr - ok - so, your cube is 800mm high as well, right?

Question: how many millimetres below the light, is your lowest coral (corals that is on the sand/substrate)?

 

[Warr7207]

Hi Warr - ok - so, your cube is 800mm high as well, right?

Question: how many millimetres below the light, is your lowest coral (corals that is on the sand/substrate)?

Lowest - Heliofungia approx. 700mm from water surface

 

[jacquesb]

OK - I think that the HelioFungia will be most likely the only one that will then not really receive the correct amount of lighting to fully make use of photosynthesis for production of energy via the zooxanthellae - It will still work, but not as efficient. This means you will have to target feed it for the coral to survive/thrive.

That said - it would be up to you to decide whether you want to upgrade to one 250 watt metal halide - which should have at most a 10000K / 14000K globe. If you add another 150 watt metal halide, you will still have the issue with the maximum depth and PAR output - even with 2 x 150 watt metal halides. The 250 watt metal halide will definitely produce much better PAR output at the maximum depth (for the heliofungia), BUT, you should then also most likely lower your other corals to a lower depth at first, to ensure that they are not light-shocked.... They would/could bleach because of light-shock....

Many people LOVE their 250 watts - at this stage I do not see the need for myself to go that route - I have 2 x 150 watt 14000K DE BLV metal halides on my 2 metre tank, with supplemental T5's (6 x 54 watt: 4 x white, 2 x actinic).....

If you want to specialize and keep only/mostly SPS, then upgrading would be a very good idea. Otherwise, the 150 watt should be more than sufficient.

 

[Alfie]

Here is some interesting facts on lighting requirements:

Coral Light Requirements

Although we generally think of corals as originating from brightly lighted natural reefs and naturally assume corals need lots of light, the truth is that most corals require relatively little in order to thrive. For example, the 'Fox' coral (Nemezophyllia sp.) does quite well in low light. Thriving specimens have been noted in as little light as 35 µMol·m²·sec! On the other hand, an Acropora specimen (commonly called the 'Purple Monster') displayed magnificent coloration in the highest light intensity I have ever measured in an aquarium - almost 900 µMol·m²·sec (later research reveal that this coral photo-saturates at 300-400 µMol·m²·sec. I was wasting a lot of light and money!). Most corals will grow quite well in light intensities of 200-300 µMol·m²·sec.

 

[Alfie]

Some conversion rates.

Converting Lux to PAR

If you have a lux meter, it is possible to convert lux to PAR. Since spectral quality plays a part in these conversions, each light source (actinic lamp, 6,500K metal halide, etc.) will have a difference factor. The equation is:
Lux ÷ Constant = µmol·m2·sec
Lux to PAR Conversion Factors Light Source
ConstantSunlight 54
Warm White Fluorescent 76
Cool White Fluorescent 74
URI (now UV) Actinic Fluorescent 18
URI (now UV) Daylight Fluorescent 54
Actinic/Daylight Combination 38
Philips 03 Actinic Fluorescent 40
Panasonic 6,700°K Power Compact 72
Panasonic 7,100°K / 6,700°K Combination 55
Osram Powerstar Metal Halide 57
Ushio 10,000°K Metal Halide 54
Coralife 10,000°K Metal Halide 30
Venture "Daylight" Metal Halide 46
Radium "Blue" Metal Halide 51
Fusion Sulfur Lamp 41
Westron Mercury Vapor Lamp 70
Iwasaki 6,500°K Metal Halide 57

 

[Bristlebasher]

BUT, you should then also most likely lower your other corals to a lower depth at first, to ensure that they are not light-shocked.... They would/could bleach because of light-shock....

No - raise the lights and then slowly lower it to the correct position. Not practical or good practice to move corals around all the time.

 

[jacquesb]

Cool BrittleBasher - you are right - thanks for correcting me.
I agree - the lighting should be raised and then lowered slowly to adjust the corals to the new stronger lighting!

Alfie - ABSOLUTELY BRILLIANT INFO MAN! Thanks! I wonder if there's ANY info on the BLV 10000K lamps.

It is EXTREMELY interesting that the "Daylight Fluorescents" have the same conversion ratio as natural sunlight!

 

[Warr7207]

OK - I think that the HelioFungia will be most likely the only one that will then not really receive the correct amount of lighting to fully make use of photosynthesis for production of energy via the zooxanthellae - It will still work, but not as efficient. This means you will have to target feed it for the coral to survive/thrive.

Weird thing is the the Heliofungia is the happiest coral in my tank. I do target feed it.

It is growing quicker than even my softies. And it hasn't moved (I have been told this is one of the only corals that can be mobile) If it was unhappy would it not try do something about it ?

 

[jacquesb]

Here is some interesting facts on lighting requirements:

Coral Light Requirements

Although we generally think of corals as originating from brightly lighted natural reefs and naturally assume corals need lots of light, the truth is that most corals require relatively little in order to thrive. For example, the 'Fox' coral (Nemezophyllia sp.) does quite well in low light. Thriving specimens have been noted in as little light as 35 µMol·m²·sec! On the other hand, an Acropora specimen (commonly called the 'Purple Monster') displayed magnificent coloration in the highest light intensity I have ever measured in an aquarium - almost 900 µMol·m²·sec (later research reveal that this coral photo-saturates at 300-400 µMol·m²·sec. I was wasting a lot of light and money!). Most corals will grow quite well in light intensities of 200-300 µMol·m²·sec.

Thanks, Alfie - I was speed-reading - so I missed out on this part of your comment.

This is actually EXTREMELY interesting. This actually staves what I was believing ALL ALONG!....

Thanks for this.