MH intensity at differnt depths

[Cutiewitbooty]

I was wondering, at how deep does a MH bulb start to loose it intensity. I have 150watt 10k bulb (whole fixture is 280watts) and i wonder if the stuff on the bottom of my tank get much light. The tank is 20" deep so at like 10" does the light get cut down much? Would clams do ok on the bottem or acroporas?

 

[spoon25]

its my understanding that the MH dont reflect much light compared to like PC's they actually give a direct light the 150 should be perfectit might not look super intence and thats a good thing but beleiev when i tell you this..the MH is a def p lus , and it does give off lots of light to the corals,when you add MH to a 25 gal tanki i beleiev its starts loosing intensities when the bulb get loike 12-18 months old, and it takes like a 100 hrs with new bulbs to start really giving off the lighting you should have..you should have no problems with the acroporas, but with that size tank a clam prolly wouldnt be wize they need lots of room cuz they get big...this is what you have a 25 gallon tall tank....

 

[steve the plumb]

you are fine my tank has a depth of 36 inches.If you decide to but acros or clams make sure you have steady paramaters.Clams are easy to keep but acros are more sesitive to changes.

 

[DJ88©]

all light loses intensity as soon as it enters the water. Even through air. You can measure this from the instant it leaves the bulb actually.

In air it is an inverse square rule. So for a doubling of the distance you only have 1/4 the intensity from original.

I can't remember if the same applies for water.

I'd watch out for SPS or high light needing clams down at the bottom with only a 150W HQI. Otherwise you should be fine.

 

[clkwrk]

Here are some lux readigns from my tank to give you an idea.

I have 250 de's

 

[Cutiewitbooty]

what do the number mean, is the the lower the higher intensity?

 

[DJ88©]

higher number = higher intensity

deeper you go, less light for corals etc.

 

[Cutiewitbooty]

hahaha, thats what i ment lol

 

[Anemonebuff]

You could get away with a maxima, crocea or dereasa on the sand. I would put the SPS from the middle up.

 

[clkwrk]

BTW here were my two clams under 150de 10kushio. Before the went to the sps tank. This was in a 24" deep tank . IMO they did great .

 

[chrismunn]

thats interesting. from 1\4 the way down, to the bottom, the lux is cut in half....

 

[clkwrk]

Heres another comparison. My 90g which has the same bulbs but different pendants.

You can see the frogspawn is getting 1200 thats only 3" below the water. and then down at the bottom 5600.

Difference is . The 90 is 2 oceanlights with mag ballast and the 120 is 3 reef optix III with icecaps. .

 

[Cutiewitbooty]

thats cool what did you use to measure that?

 

[clkwrk]

milwaukee lux meter

 

[Cutiewitbooty]

I bet thats a cool toy, i might have to pick one up

 

[Anemonebuff]

Do you have a link?

 

[Cutiewitbooty]

i looked on ebay and they have a few

 

[clkwrk]

http://milwaukeetesters.com/english/products/economy_portable_meters/SM700.html