T5HO Height above water surface?

[Scythanith]

Simple one, how high should I mount my new T5HO with IC SLR's from the water surface? I'm aiming for ~4" So I have a good space for airflow from some 4" fans along the bulbs length.

Opinions and suggestions welcome!

 

[sasscuba]

I have mine at 4.5.

 

[blmeier7]

My T5's are about 5" off of the water surface. If you can go 4" that would be good. Mine are higher just to keep the heat down some.

 

[corals b 4 bills]

Guys- right now I am watching a video of anthony calfo discussing t5 heights, he said the closer to the water as safly possible, anything over 3" off the water's surface the corals are only getting maybe 10% of what they need to feed from the light, 4" or more he said you might as well just turn them off. (reef videos.com)

 

[Scythanith]

OK then, this raises a new question..... how do I get enough airflow across the length of the bulbs to keep them cool if I put them real low?

 

[blmeier7]

coralb4bills--thanks for the link.

I completely agree with "the closer the better" but I can't believe that anything over 4" is worthless. Like I mentioned above--I have been running mine 5" above the surface for the past 18+ months and I have been getting good growth from my corals. Even my pink birdsnest has doubled in size and been fragged many times.

I will try lowering the lights to 3" (if I can get away with it heat wise) and see what difference it makes.

 

[sasscuba]

<a href=showthread.php?s=&postid=9984054#post9984054 target=_blank>Originally posted</a> by corals b 4 bills
Guys- right now I am watching a video of anthony calfo discussing t5 heights, he said the closer to the water as safly possible, anything over 3" off the water's surface the corals are only getting maybe 10% of what they need to feed from the light, 4" or more he said you might as well just turn them off. (reef videos.com)

What a crock of BS. My SPS and soft corals grow like crazy at 4.5 inches off water. Buddy has his 10 off water in a canopy and his grows better than mine......:rolleye1:

 

[sasscuba]

Where is the said video? I don't see it on that site?

 

[hulley]

I dont see how a couple of inches of "air" would make that big of a difference. I get the water depth because of the particle in water blocking light rays and such, but there isnt much in the air to block that a few inches would matter. I just ordered a t5 retro kit and am hoping to mount it about 10in above the water, I really dont want to have to lower the lights.

 

[jessezm]

<a href=showthread.php?s=&postid=9984619#post9984619 target=_blank>Originally posted</a> by sasscuba
What a crock of BS. My SPS and soft corals grow like crazy at 4.5 inches off water. Buddy has his 10 off water in a canopy and his grows better than mine......:rolleye1:

Agreed--I just can't see how that could possibly be true. My T5's are 7-8" off the water, with a 1/2" acrylic brace blocking direct light in some places, and I had a millipora bleach out at about 12-14" depth. My acros are growing great, and at the bottom of my 30" tank, I have LPS (euphylia and fungia), zoos, anomones, and montipora all thriving. These are not overdriven, either--just 4X54Watt, 2X36Watts, and 2X24Watts over a corner pentagon tank, all with Ice Cap reflectors. I am not able to believe that anthony calfo could really have meant that...

 

[corals b 4 bills]

There are 24 videos and the click on one of the little boxes that says Anthony Calfo video, about half way through he talks about buying or borrowing a light or par meter and measuring from 1 to 3 inches after 3 he measured approx. 10% of the actual light would be able to penetrate 24 to 30 inch tank, watch the vid. also check out Eric Borman's oxygen seminar,very cool.