SPS dominated tanks, how high are you lights mounted?

[143MPCo]

Looking to see if there's a sweet spot for mounting MH fixtures or any other lighting fixture that you have used and received either excellent, or not so good results... Trying to gauge the best placement height not related to PAR although that is a factor but, more for general light spread along with in tank accessibility.

What do you all do?

 

[FoD]

On a 4' tank I have my ATI 8-Lamp 6" above water line. This fixture will be moving over a 10" deep frag tank shortly, and will be mounted at least 12" up, with the ability to go to 16". My main display (2x250w Radiums with 4x80w T5 and 4 Kessil A160We) will be at 5" above water line, on a motorized lift to go to 18" to allow my Moose-sized body in there to work inside the tank.

 

[twilliard]

My atlantik is 14 inches above the water (led)

 

[fraghunter]

My 8 bulb 24" ATI with 2 24" xho reefbrite actinic are mounted 5" off the water line on a 60 cube 2x2x2

 

[143MPCo]

On a 4' tank I have my ATI 8-Lamp 6" above water line. This fixture will be moving over a 10" deep frag tank shortly, and will be mounted at least 12" up, with the ability to go to 16". My main display (2x250w Radiums with 4x80w T5 and 4 Kessil A160We) will be at 5" above water line, on a motorized lift to go to 18" to allow my Moose-sized body in there to work inside the tank.

Thanks, really good info!

My atlantik is 14 inches above the water (led)

How deep is your tank?

My 8 bulb 24" ATI with 2 24" xho reefbrite actinic are mounted 5" off the water line on a 60 cube 2x2x2

Thus far it seems like 5" is turning out to be the normal height...hmmm

 

[fraghunter]

I had them at about 8-10" off water line everything looked good but when I went to 5" a couple of weeks latter everything seemed happier better polyp extension and the colors really started poping. Don't think I would go this low with MH though unless you had some fans moving air

 

[twilliard]

20 inches deep

 

[143MPCo]

Don't think I would go this low with MH though unless you had some fans moving air

Good point... My MH unit has a built in cooling system, one thing I noticed right away was how cool to the touch the top of the Cebu stayed, that's not to say it won't warm the water a bit but, I'm open top and fans blow across the raceway.

 

[jeremy]

I have a 48 inch 8 bulb ATI Sunpower over a 48x24x24 all sps tank. Fixture is 9 inches above water. Plenty of light.

 

[LVE]

I have LED's and they're about 6 inches above the water.

 

[143MPCo]

Seem like, depending on wattage and or if using MH or LEDs, that anywhere from 5" to about 8" seems to be the norm?

 

[d2mini]

My Cebu is mounted 10" above the water.
That's as high as I can go. I need better spread since my tank is 84" long.

 

[143MPCo]

My Cebu is mounted 10" above the water.
That's as high as I can go. I need better spread since my tank is 84" long.

10"!?!? You had to go throw a monkey wrench in my hypothesis[emoji12].

 

[AdamNC]

8 inches on a 18 in deep tank

 

[KJ]

LED 16''above . I'm happy with.

 

[Rob.D]

I think it goes
8"- 12"- for 150 watt
12-16" for 250 and 400 watt

LED fixture manufactures typically have a suggested height positioning for best PAR/light spread. Personally, I've found 14"-16" to be best.

 

[WilRams]

Would you use the same general rule of thumb on a shallow tank or adjust accordingly?

 

[143MPCo]

@Rob.D thank you Sir!!!

 

[143MPCo]

Thank you all for the replies

 

[Rob.D]

Would you use the same general rule of thumb on a shallow tank or adjust accordingly?

I ran MH and LED over a 12" deep tank, I got the best results from positioning the lights higher up for optimal light spread.