Led balance help

[chrlstnsurf]

Led lighting help
I have a 25 gallon cube with a Ocean Revive t247 full spectrum LED fixture with 90 degree optics. I have it hung about 9 inches over the tank. I am having trouble figuring out when to stop raising my whites. Right now I have my blues at 100 and whites at 65. Everything seems to be doing great with the exception of my Candy Canes. My question is when will I know that my whites are too high? I know to look out for bleaching but I don't want to even get to that point. Anyone else have a fixture like this or similar so I can compare the balance?

 

[Ron Reefman]

OK, so now I get to your 3rd post about the issue you are having and this time there is more info, thanks. However, telling us how deep the tank is would be better than saying it's a 25g cube. Is it roughly 18"x18"x18"?

IMHO, running your blues at 100% is risky if your tank is less than 18" deep. And 100% blue and 65% white would be a relatively high PAR even for a 24" deep tank. Maybe not too high, but IMHO, it would be very close to the upper limit.

Nobody can tell you at what level your white will be too much, it's too subjective (depth of the coral in the water, height of the fixture off the water, clarity of the water, location of the corals under the center of the fixture vs around the edges, water flow, surface agitation... ). Readings from a PAR meter would help and I do have one as well as an OR T247 fixture over my frag tank.

If you asked me for basic settings over an 18" deep tank with the fixture 9" off the water, I'd say something like... 60% to 80% blue and 20% to 40% white. That should be enough for most any corals.

I hope that helps?

Now if those settings make a tank that has a white that is too cool (blue) for your taste, dial back the blue and add some white. That should give you a warmer white look.

Just remember that the zooxanthellae that live inside the coral polyps use way more blue to do photosynthesis than they do white. White helps the coral some for both photosynthesis and creation of pigments (coral coloration), but blue allows the zooxanthellae to really feed the coral and keep it healthy.

 

[chrlstnsurf]

I will measure today when I'm off from work. Most of my corals are centered in the middle with the exception of my couple of LPS that are at the bottom. The reason for my blues being so high is bc I have mostly an SPS tank. Everything seems to be doing great but maybe I will look into dialing it back. The other reason I increased is because my Rainbow Rose Anenome moved from where I had it to the very top of the tank and has been loving it. I know they require lots of light so figured I didn't have enough.

 

[Ron Reefman]

I run my OR T247 over a frag tank that is only 14" deep, but the fixture is 2' off the water so I have room to work under it. I have mostly sps frags and currently have 5 RBTA as well.

I'm running 90% blue and 10% white. Everything in the tank is growing and colored up as well as I could ask for.

 

[chrlstnsurf]

So let's say my tank is 18 inches. From what I read 8 to 9 inches above is ideal. Could I be wrong on this? Could dropping it down help? Without a PAR meter I'm pretty much just ****ing in the wind. Why may I ask is yours so low to the surface?

 

[Ron Reefman]

A) The distance between the fixture and the water is almost completely unimportant since you have dimmers. Set it closer and dim the light a little. Move it higher and set the dimmers a bit brighter. There is only one good reason to consider the height off the water. You want the fixture high enough so the light fills the tank with a minimum of 'spill' outside the tank. Higher makes a bigger footprint of light and lower makes a smaller footprint of light.

B) My fixture is farther away from the water than almost anybody would set one because I work in the tank and need the room between the water and the fixture. Mine is 2' (that's 2 feet not 2 inches) from the water.