How much PAR is too much?

[MechEng99]

Hi!

I'm in the process of upgrading from a 40g SPS-dominant aquarium to a 150g SPS-dominant aquarium. My previous lighting maximum PAR was about 250 on the highest rocks, and down to about 100 on the sandbed.

The new 150g aquarium is 31" tall, so we wanted to make sure we had enough light to grow SPS lower in the tank. We purchased/installed 2 x 400W metal halides on IceCap ballasts, used in two LumenMax Elite reflectors. T-5 supplemental lighting is 420 and 460nm (2 x 54W bulbs).

Our plan worked a bit too well since PAR is 430 on the brightest spot on the sandbed. The brightest rock is 725.

I know this is well above the photosaturation/photoinhibition level of most (if not all) SPS corals (and I really don't want this to be a softy tank).

Is anyone else running an SPS tank with these sort of PAR values successfully? How did you acclimate your corals? Should we just run screen under the bulbs 24/7? Buy new 250W ballasts/bulbs (ugggh!)?

Thanks!

 

[MechEng99]

Oh, btw, the lights are about 10" off the top of the water. The stand/canopy/ceiling prevent us from raising the lights higher.

 

[chadfarmer]

You will have to aclimate your corals to the light

 

[MechEng99]

Yup...realize that all too well. Fully prepared to do that with screen, adjustable racks, etc. Question is...will they acclimate (ever) to PAR that high? I realize the sun is bright and all that, but I'm not aware of what the PAR in the ocean is...or how well the corals will survive under higher than photosaturation levels.

I was more wondering who has an SPS tank with PAR values this high...and the corals aren't bleaching to death (regardless of acclimation).

 

[reefried]

.....those numbers are not that high esp on the sides of your tank of course you'd have to acclimate frags and such but you'll be fine long-term, check out the current totm....................http://www.reefcentral.com/forums/showthread.php?s=&threadid=1641235

 

[ksc]

I'd say those numbers are pretty average for an SPS tank. As far as photoinhibition, not even close...
http://www.fishchannel.com/saltwater-aquariums/aquarium-frontiers/natural-reef-light.aspx

 

[jd474]

PAR levels in nature are ~1500 - 2000+ in high light areas. Like others have said, acclimate your corals accordingly.

 

[OwenInAZ]

I have almost the same setup as you, except mine is 90G not 150G. It's an odd shape that was somewhat dictated by the amount of real estate available for the footprint (18"x36"x31"). I have 2 400W Reeflux 12Ks, and while I've never taken PAR readings, I'd wager ours are similar.

I grow SPS (primarily digi's and milli's) up on the highest rocks exceedingly well, and I have at least a couple down in your 400-500 range.

To acclimate, I just leave the frag on the sandbed for a week or so, then move it up to wherever I'm going to put it. So far so good. HTH.

 

[MechEng99]

Thanks everyone! Just what I was looking to read. Don't know why I had such a hard time finding the info without asking.

Owen - thanks for the info on your setup! We were also dictated by space (hubby said I could only have a 4' tank, so I cheated and got one as tall as easily possible.)

 

[OwenInAZ]

Thanks everyone! Just what I was looking to read. Don't know why I had such a hard time finding the info without asking.

Owen - thanks for the info on your setup! We were also dictated by space (hubby said I could only have a 4' tank, so I cheated and got one as tall as easily possible.)

Ha, my wife said I was restricted for space! I had a 4' 80G that wasn't drilled, wanted to get the full kit, so I *had* to get a new Lee Mar. She told me there had to be room for a table next to the couch so here we are

The only (ONLY) reason I can get away with such a tall tank is my big monkey arms. I'm 6'3" tall and sometimes I need to employ a set of forceps to get things off the bottom. I love the amount of vertical real estate I have to play with, but good luck with keeping crap clean on the sand

I really do think you'll be fine for pretty much anything you want to keep in that tank. I have to keep my LPS colonies at or below ~50% of the tank height, but my SPS can grow pretty low in the water column. I haven't tried any softies off the sandbed, except for one colony of zoas that thrives about 6-7" up on a rock.

 

[serpentman]

I agree that those PAR levels aren't too high. However, keep in mind that they are also not necessary to get good growth. My tank ranges from 700-200. I've got plenty of SPS that grow like weeds in the 200-300 range.

If for some reason you find your corals are having trouble adapting, you can always raise your lights.

 

[MechEng99]

Owen - you're lucky with your long arms! Thankfully my husband has long arms too, b/c I sure don't!! It's been a bit of a challenge so far maintaining the bottom half of the tank, but I love the height.

Serpentman, thanks for the info on your tank. Unfortunately, due to our stand/canopy/ceiling restrictions, we can't raise the lights.

 

[shaggy14]

I am using the elite reflectors but in the 250w on my tank. The highest light points are near 1200par. I have a setosa that I acclimated that is right under the light in the 1100-1200 range. Just started it at 2 hours a day an slowl moved up to the four hours I'm at right now. Eventually will have it back to my six hour cycle

 

[MechEng99]

Shaggy - wow, that's some crazy PAR with the 250s. How far below the lights is that (in water?) What ballasts/bulbs? I'm no where near that with my 400s.

How long has that Setosa been in 1100-1200 PAR?

 

[shaggy14]

the reflectors are between 4-6 inches off the surface of the water and the setosa is about 7 inches deep. i am running lumatek ballasts and the reflector in the middle(where the setosa is) is running a single ended phoenix 14k. the bulb was about 4-5 months old9running 4 hours a day for the midday effect on my 90g) when the reading was taken. i set up the 210 in late feb, early march of this year and moved over the contents of my 90. i had a little bleaching at first and the setosa was starting to turn a neon pinkish color so i cut the time back to 2 hours. i have been slowly moving it up 30-60 minutes every few weeks, whenever i think about it.

 

[zaheda]

I wonder what par is using 20k BLV bulb with a magnetic ballasts, with diy large lamenarc reflecter.

 

[stanlalee]

PAR levels in nature are ~1500 - 2000+ in high light areas. Like others have said, acclimate your corals accordingly.

those are peak numbers that last one hour a day on nice sunny days. I agree they can adapt to the numbers posted but its apples and oranges from a continous consistant high PAR 6-8hrs/day no relief light source 365 days a year.

 

[BradR]

It's been a couple months and my corals still aren't used to 400W 14K Ushios in mini wide lumenbright III reflectors 24"-36" from them. Still have screendoor material under the lights as the corals are so light just running the bulbs around 4 hours a day. So yes, I think you can have too much par. It also depends on the coral too though. My milleporas seem to tolerate the high par better. One of the reflectors has a 20K Radium and those corals don't need the screen material and are doing well.