PAR for SPS QT

[lee_d_m]

Hi

I'm putting together a QT for my acros due to AEFW. I have a 4 x 24w T5 light unit that I have just installed 4 new ATI tubes into.

The QT tank is a 2 foot cube and with the light sitting on the tanks brace bars I'm only measuring 150 PAR 1 foot directly below the light in water.

I was expecting more to be honest so I would like to know whether this is going to be sufficient to sustain my acros for approximately 6 weeks or do I need to add more light ?

Thanks

Lee

 

[pisanoal]

Hi

I'm putting together a QT for my acros due to AEFW. I have a 4 x 24w T5 light unit that I have just installed 4 new ATI tubes into.

The QT tank is a 2 foot cube and with the light sitting on the tanks brace bars I'm only measuring 150 PAR 1 foot directly below the light in water.

I was expecting more to be honest so I would like to know whether this is going to be sufficient to sustain my acros for approximately 6 weeks or do I need to add more light ?

Thanks

Lee

Someone else would have to chime in, but that seems awful weak for that light if its that close to the water. Im guessing you are measuring just below water line, so 4-6" below fixture and maybe an inch into the water?

If you had 150 where you were going to have your sps, then Id say they'd be fine for a couple months (probably lose some color). But if its 150 just below the water, you would probably struggle.

 

[bobssecrtsn]

Par dramatically drops as you lower, also surface flow etc.


depending on reflectors, they may be bad, or if you have really bad reflectors. it will cause low par measurements.

Theres also bad par meter. which brand are you using. DIY? did you multiply the readings correctly.

4 24" ati bulbs should put out more then 200+ par on the surface.

 

[lee_d_m]

Thanks for your responses, let me explain a bit clearer what I'm seeing.

Tank is 2ft x 2ft x 2ft, light is sitting on brace bar directly above center of tank, so let's say about 2ft above the bottom of the tank.

Water level in the tank right now is just over 1ft deep.

When I put my PAR meter a distance of 1ft below the light, just submerged in the water, the PAR is 150.

If I put my PAR meter out of the water a couple of inches from the light then the PAR is well over 200.

PAR meter is an Apogee quantum sensor and it's working fine.

hope that makes sense, my questions are:

Is this the PAR output I should expect of 96w of T5's and
Is this amount of light output sufficient to keep my SPS alive for 6 weeks whilst they are treated for AEFW

Thanks

Lee

 

[pisanoal]

Are you keeping the tank only half full? If I were you, I would fill it to the "top", and check par maybe 6 inches under the water surface. I think your measurement is a bit deceiving because of how low your water level is. As someone else mention, par drops dramatically as you get further into the water. I believe its exponential. It doesn't drop as bad out of water, but will still drop fairly quick as the light spreads out from the main source. So I would bring my water level as close to the top as I was comfortable, test par 4-6" below water line, if I hit 150 there, I would feel pretty good. Then build a rack so that is the height where your corals sit.

Edit: And yes, depending on the fixture and reflectors, at the distance you are talking about, I would think that is reasonable output for a 4 bulb T5

 

[lee_d_m]

Hi thanks for your response

I'm currently filling the tank so the water is lower than it will be eventually and will be building a rack so that the corals are in the top half of the tank, so would you say that if the PAR is at 150 where the corals are placed they should be ok ?

 

[pisanoal]

Hi thanks for your response

I'm currently filling the tank so the water is lower than it will be eventually and will be building a rack so that the corals are in the top half of the tank, so would you say that if the PAR is at 150 where the corals are placed they should be ok ?

Yes, I would think so. SPS can tolerate lower light levels for a few months. You can always supplement with some feedings too if you are worried about it.

Sahin posted a chart from an aquaculture farm a couple years ago that showed a lot of sps/acros pretty happy around 150 par. You would probably expect some color degradation though, although with the AEFW treatments, you will probably see some anyway.

 

[lee_d_m]

Ok thanks, I'm certainly not concerned about colour, survival is of utmost importance, will see if I ca find that info from Sahin

Thanks again

 

[MichaelW]

150 par is plenty to keep sps alive.