BTA under par 38?

[Eastamherstbias]

Does anyone have a BTA under a par 38?

I put a par 38 to shine on a rock in my mangrove tank and I was looking to put a BTA on the island rock so my orphaned Latz can host in it. Is that enough light? It is only a 20L tank.

 

[Jacwil]

I had a RBTA in an 18" cube, half-way up the stack, with a NT Par 38, 20k with 60 degree optics, for about 8 months...did fine and never moved. I broke that system down, hence the short 8 month period.

 

[Eastamherstbias]

How far was the par 38 off the water? I have the Evil Par 38 20k with 80 degree optics.

 

[Jacwil]

Ooops...meant to include that as well. Probably about 10-12".

 

[Eastamherstbias]

ok cool, I will drop it to 8 inches next week since I have wider optics.

 

[Jacwil]

So your lamp will penetrate a touch deeper. You are "dropping" what to 8"?

 

[Eastamherstbias]

I am 13 inches above the water right now. I was planning on going to 8 inches above the water after I let the BTA adjust for a few days.

 

[Jacwil]

Ok...my 'nem was approx. 20" from the light and appeared happy. Your lamp can punch deeper so it doesn't necessarily need to be closer.

lol...just making sure we're on the same page.

:beer:

Found an old pic and included...it looks like the lamp is about 12" above the water.

 

[Eastamherstbias]

Cool, thanks

 

[cardiffgiant]

I've been having some challenges with growth and coloration in my new frag tank. When I set it up I raised the PAR38's to about 15-17" off of the surface of my 20 long. My frags are only a few inches deep, so I was afraid of cooking them. I've had a much harder time with SPS than I used to.

In the previous set up, the frags were a few inches deeper, but the light was about 10" off of the surface.

Anyway, I was doing some research on PAR38 threads, and came across this one with someone positng his experience with BTA's. Looks like he had issues at first, but that they did acclimate within a few weeks.
http://www.reefcentral.com/forums/showthread.php?p=18745215

 

[Eastamherstbias]

Yeah my LED frag tanks have excellent growth on Toadstools, Palys, Meteor & Birdsnest corals. Sps does seem to suffer.

 

[IronMan72]

ok cool, I will drop it to 8 inches next week since I have wider optics.

So your lamp will penetrate a touch deeper. You are "dropping" what to 8"?

OK, I'm confused. Wouldn't 80 degree optics have a wider beam width than 60 degree optics? I assumed that the angle specified for the optics referred to how wide the light beam was spread at a specific distance from the lens. In this case 80 degree optics would spread the light over an 80 degree arc. So the 80's would spread the same light over a 20 degree wider area than the 60's. Wouldn't the 60 degree optics concentrate the light into a smaller beam and therefore penetrate deeper and to a more localized area that the 80 degree optics?

 

[Jacwil]

Lol...you're absolutely right...I misspoke.

 

[IronMan72]

Whew, you had me concerned that someone changed the laws of physics without telling me.

 

[Jacwil]

Funny man!

:beer:

 

[Eastamherstbias]

I moved the par 38 into the mangrove tank. The elegance coral apparently loves the extra light. The light is 12 inches from the water line. In the next week, I will add a small RBTA for the latz clown.

 

[Eastamherstbias]

I picked up two bubble tipped anemones. I have the par 38 12k 80 optics 9 inches off the water and the anemones are 9 inches under the water. The latz is already in one of them and appears happy. Hopefully enough light/par.

 

[Jacwil]

Very cool! Keep us updated!

 

[Eastamherstbias]

here are better pictures

 

[Eastamherstbias]

Updates. The anemones keep moving around. I think/hope they are adjusting. The latz is jumping between the two. I moved the elegance coral to it's own island rock I built so it is safe from the rbtas.