Low PAR increase photosynthesis?

[thabizness]

Is the reason why WWC's lighting is so low is the 14 hour photo period? Most of us using 8-10 hours. If we extened our normal period to their business day we would burn corals and have to lower par.

Maybe I missed it but the people who are running lower par - are they running longer photo periods?

 

[ludnix]

Here's an image I generated for a friends tank. We did measurements before and after a bulb replacement, which might interest you all. I found his tank to be absolutely spectacular but the numbers were a lot lower in many places than we expected. That said, the massive colony of GARF bonsai is sitting right under the hamilton MH at around 500 PAR. All measurements were taken on a SQ-420 which should be accurate for MH but perhaps less so on a LED tank.

Sorry for JPG compression, had to pull this off our FB group as I'm not sure where the original file is.

 

[Centerline]

Ya'll mentioned WWC and it made me remember this:
http://ecotechmarine.com/wp-content/uploads/2016/11/World_Wide_Corals_Coral-lab_03.pdf

"WWC's Radion schedule is unique because it is designed to provide lighting for the duration of business hours. In order to prevent over-lighting due to the extended photoperiod, the overall intensity is set lower than what would be required for a shorter photoperiod. In the Aquaculture Facility, WWC uses AquaIllumination Hydra 52HD units on their SPS run. On their other troughs which are largely soft corals, LPS and deep water SPS, they use T5 ATI Aqua Blue Specials and Blue Plus bulbs at a ratio of 3:1 per fixture. In most cases a Reef Brite HXL strip is used to supplement the T5s. The SPS aquaculture run using AI Hydra lighting receives PAR exposure in the 250-275 range, the LPS and Deep Water corals under the T5 lighting receives 80-140 PAR."

They certainly aren't blasting anything.

No, they really arent. They have so much water volume that its a very, very stable environment. And from testing water from multiple corals I've purchased at the store there are no crazy numbers anywhere - 8ish DKH, 400ish Cal, 1350ish Mg. Nothing crazy at all - except the consistency of the environment and enviable attention to detail.

 

[Centerline]

Here's an image I generated for a friends tank. We did measurements before and after a bulb replacement, which might interest you all. I found his tank to be absolutely spectacular but the numbers were a lot lower in many places than we expected. That said, the massive colony of GARF bonsai is sitting right under the hamilton MH at around 500 PAR. All measurements were taken on a SQ-420 which should be accurate for MH but perhaps less so on a LED tank.

Sorry for JPG compression, had to pull this off our FB group as I'm not sure where the original file is.

That's some cray drop off after 9 months. I usually loose about 15% par on my MHs after a year. How many T5s does he have?

 

[WetWhistle]

I learned a long time ago questions like this are trick questions. There is no number that is best for coral growth just tolerances. Trying to find the best is just chasing number. What is best for growth and color in my system doesn't mean it will be best for someone else. Lighting is just one factor that influences coral growth and is not the most important. You can have all the light in the world or lack of and if you don't have the building blocks needs for growth and calcification you will not get much out of it. To high a light level and you pass the light saturation level and calcification stops. The same is true for to low a level calcification slows or stops. Water chemistry, nutrients, available food for active feeding and water flow to bring food and nutrients to corals all factor into how fast a coral grows.
If you look at growth data on calcification, growth rates are not at there peak during daylight hrs but at night when the coral is at rest and actively feeding. Active feeding provides higher nutrients for coral growth that go towards calcification then zooxanthellae do towards the energy budget. As zooxanthellae are greedy and are looking out for themselves and only leach extra energy to the corals once they have what they need. The majority of energy from active feeding typically goes towards calcification because most of it by passes the zooxanthellae. Eric Borneman has a excellent chapter on calcification and what all factor into it in his book 'Aquarium Corals: Selection, Husbandry, and Natural History' for those of you that want more info on this. I quite enjoyed this chapter.

I myself run my light levels high at 86% for LED so I get lots of light. I run the LED for 12 hrs with 30 min ramp up and down. The only change in intensity for me is an hr and half when my T5 come on for a PEAK time in the middle of the day. I keep my ALK at 10 as I find it supports a PH range of 8.2-8.3 and I get better growth rates from it. I don't run a skimmer all the time so I do have available nutrients. After I added the T5 and without any other change my calcification rates and coral growth exploded. I have to trim most of my coral weekly to keep growth under check. Especially the fast growth ones that encrust like Monti. I have tested all rages over the years and I find this mix works best for me and the way I run my system.

I personally find to high a light level worse then to low. To low you can make up somewhat by more feeding, but to high is hard. As you need to add O2 and increase water flow to maximize gas exchange. To be honest for most people for light level somewhere in the middle will get you best growth with extra feeding.

 

[ludnix]

That's some cray drop off after 9 months. I usually loose about 15% par on my MHs after a year. How many T5s does he have?

I think it's a Hamilton Cebu Sun, so it should have been 4x T5 bulbs and 2x 250w MH. I think the drop was pretty crazy too. The glass on the fixture was cleaned as well, but it was surprisingly clean already.

 

[Centerline]

I think it's a Hamilton Cebu Sun, so it should have been 4x T5 bulbs and 2x 250w MH. I think the drop was pretty crazy too. The glass on the fixture was cleaned as well, but it was surprisingly clean already.

Could be the ballast killing the bulb prematurely or something. Certainly a large drop in over driven T5s would be expected as well. Interesting non the less. Thanks for the info!.

 

[ludnix]

Could be the ballast killing the bulb prematurely or something. Certainly a large drop in over driven T5s would be expected as well. Interesting non the less. Thanks for the info!.

That or my buddy misremembered when he changed his bulbs last! I will definitely be interested to see how long they last over the next few months and see if we can get a reading again before he replaces. If he is killing the bulbs early via a bad ballast I think he will want to know. Thanks for the possible explanation, I hadn't considered it.

 

[mcarroll]

Here's an image I generated for a friends tank. We did measurements before and after a bulb replacement, which might interest you all.

Thank you for posting this!!!

@saltyfilmfolks I could be looking at an old:new differential like this on those Radium measurements I recently did.

 

[hart24601]

For everyone that doesn't have time to watch the entire video:

YAY! I have never seen that, but every time I see a thread talking about light intensity I always try and chime in that intensity is very much linked to flow. Saying I found my particular acro to grow best under 350 PAR is not very useful unless I say how much flow that area gets. I know that is hard to judge, but at least a ball park. 350 PAR in a lower flow environment may very well lead that same coral to bleaching from overheating.

And when talking about growth PAR and flow are even more important to link!

Of course this is just for the sake of debate, for real world maximizing growth it's all about feeding. Feeding and flow have a far greater impact on growth than light intensity provided you are not either far under the coral's useable PAR range or far exceeding it.