Thoughts on low(?) PAR with SPS and LEDs?

[Velcro]

I thought it was pretty interesting when looking at WWC's display tanks that the number of fixtures was less and the height was higher than I would expect on such amazing SPS tanks. I believe I have read that their tanks don't see more than like... 350 PAR at the surface of the water?

This brings me to my current situation. I'm used to running 350+ PAR on my systems with T5. I've also got a new system running that is LED only with radion G3 pro fixtures and their diffusers. The tank is a 150 DD (36x36x27). I have the lights a good 15"+ above the water. I'm running three fixtures right in a row in the center of the aquarium and seeing like 250 PAR at the top of my rockwork. At first I was concerned that this wasn't going to be enough, but as I said, the WWC numbers and method has me wondering.

I believe I've also head that vivid runs relatively low PAR with these fixtures as well.

 

[nautical_nathaniel]

If your SPS corals are currently happy and growing, I wouldn't change anything.

I don't know the exact par I'm running but I imagine it's somewhere in the range of 200-250 par at the top of my aquascape. The only coral in my tank that didn't like that was my blastomussa which needed to be moved lower in the tank anyways. I've seen a very positive change from my acropora since I upped the intensity.

 

[Dana Riddle]

The tank is 27" deep - how deep is the top of your rock?

 

[Velcro]

The tank is 27" deep - how deep is the top of your rock?

roughly 12" down.

 

[mcarroll]

That's 50 more PAR @12" under water than my 19" stony tank gets at the surface.

2¢

 

[Dana Riddle]

Long distance analyses of aquarium problems is always difficult and sometimes impossible. However, I don't think your tank is over-illuminated but as was mentioned earlier, perhaps acclimation was an issue?
See here (photo #20) of Acropora specimens growing at a depth of 250 feet:
https://www.advancedaquarist.com/2007/3/aafeature1
The idea that all SPS corals require high light is nonsense. Many SPS (including Acropora species) contain Clade C zooxanthellae which are actually less tolerant of high light than other clades.

 

[jda]

...few things. Vivid and WWC tanks are fun for beginners to look at, but the people with lots of experience quickly discount their stuff. I have seen both personally and they are about 75-80% of what they could be if they did things differently. I totally get why they are done this way - they are in retail. They are the "microwave bacon" of reef tanks... really awesome to people who have not had or seen real bacon with their own eyes... or people who know the difference and just will live with the ease and convenience. You can do better than them. I would shoot for these tanks to be your floor, not your ceiling. I tend to tick a lot of people off with these opinions, but some will PM me a year later and tell me that they now can see what I was talking about.

Second, whatever somebody else does will not really matter in your home. You are a good hobbyists, so go with what your eyes tell you.

Third, PAR numbers from different light sources are not the same and cannot really be compared. Equal PAR from a Radion will be actually a lot less from T5 and especially MH that have output that the PAR meter cannot read, or cannot read accurately, but the corals can get benefit from. Again, another reason to go with your eyes, or make sure that the PAR from another light source is about 20% (rough) less when comparing to LED.

If long-term SPS is your goal, then Dr. Joshi can be a better role model with LED use, IMO. Copps, JB, Ed, etc. are also really good, but they do not use LEDs. There are a lot of other great hobbysts that crush the results at Vivid and WWC, but info on a lot of these tanks can be hard to come by.

Another opinion where I make people mad is with quality. I am of the opinion that coral can handle more PAR from a high quality light source like most T5 and MH whereas they can get burnt by a lot of LEDs since they have peaks, valleys and missing spectrum that is lower quality. Everything that I have based this on is anecdotal, but it is true that 500 PAR from my MH will make acropora thrive whereas 500 PAR from a Radion will fry them to actual death... so something has to give. Many will disagree with me on this.

 

[ESH]

Coral labs has an interesting article done on WWC when they switched to radions. They discuss their light settings and list numbers in specific tanks, and also discuss flow with their setups. What stood out to me was that they state they have lower numbers specifically for their retail operations as they are running longer than normal hours.

I’m too new to the hobby, definitely not an expert on LED lighting. I’m finding consistency is key. Initially I changed things too much thinking I should be using someone else’s settings because they are having great results. Then every time I changed things, when things didn’t go how I thought it should go I found something new. I’ve since kept a modified version of what WWC is running. Same hours, just increased intensity. I’ve had to find by trial and error what levels work for different types of corals along with proper placement in the tank.

I don’t think there is one program setting that is better than another. I don’t think there’s a specific answer to what the best settings are. Mapping out par levels through out your tank are certainly going to help, more importantly keep things consistent.

 

[oreo54]

What stood out to me was that they state they have lower numbers specifically for their retail operations as they are running longer than normal hours.

Daily light integral...

Daily light integral (DLI) describes the number of photosynthetically active photons (individual particles of light in the 400-700 nm range) that are delivered to a specific area over a 24-hour period.

 

[mcarroll]

The concept behind DLI is one that lots of folks used (or at least stumbled on) back in the day running halide systems that were over-powered.
(I think it was called something other that DLI back then.)

For example...

At the water surface, my dual-150w halide system that I started with probably put down around 80,000 lux with new 20,000K bulbs.

And I ran it for 13 hours a day at one point!! (proved some things along the way, so good experiment)

...until someone "stumbled me" on the 4-6 hour day.

All of a sudden my bulbs were lasting twice as long and my SPS stopped getting blistered tissue.

BTW, they never looked unhealthy to me (large colonies, bright colors, fast growth), but I've never seen anyone else's corals blister like that.....it was green and red M. cap. growing near the surface that would do it. Especially when the bulbs were ready to be replaced. Left to guess I'd say it was a side-effect of super-fast growth....that doesn't do much to explain it though. ;Muted

 

[revhtree]

Long distance analyses of aquarium problems is always difficult and sometimes impossible. However, I don't think your tank is over-illuminated but as was mentioned earlier, perhaps acclimation was an issue?
See here (photo #20) of Acropora specimens growing at a depth of 250 feet:
https://www.advancedaquarist.com/2007/3/aafeature1
The idea that all SPS corals require high light is nonsense. Many SPS (including Acropora species) contain Clade C zooxanthellae which are actually less tolerant of high light than other clades.

I'm always learning here at R2R!

 

[ESH]

Same, good info!

 

[BigJohnny]

There is more than one way to skin a cat, it's as simple as that. No one way is better than the other, and PAR is obviously not the only thing that determines success. Corals can acclimate and thrive in a variety of conditions, stability is way more important.