Lighting/PAR help

[Donny41]

Just tested my par numbers with an apogee mq 510. Tank is a reefer 250 lighted with 2 hydra 26 hds mounted on a 24 in. aquatic life t5 fixture. Peak numbers with the t5s and leds on are on the high 400s around the rocks. Peak with just the LEDs are in the high 300s. My current schedule runs the LEDs at peak intensity for 3 hours with the t5s on for 1.5 hours during that. Should I ditch the t5s and just go with the LEDs? All of my corals are currently growing but a few of them are not coloring up as much as I would like, and I'm thinking that could be due to them getting too much light.

 

[Ron Reefman]

Too much light could be part of the problem. I'd reduce the led levels while the t5s are on so the combined PAR was about 300. You might run the t5s for more than 1.5 hours. I'd suggest 6 or 7 hours of leds and 4 to all 7 hours with the t5s.

You might also run your photo period longer. Some coral will do photosynthesis for as long as 6 or 7 hours before shutting down.

 

[Donny41]

Run them at max for that long? (Well not max but at a par closer too 300?) Right now my light schedule is 11 am to 9 pm, but only max intensity from 2-5

 

[Ron Reefman]

Run them at max for that long? (Well not max but at a par closer too 300?) Right now my light schedule is 11 am to 9 pm, but only max intensity from 2-5

Then the question is; how close to max is the hour or 2 before max and an hour or 2 after max? If it's close, then you photo period that is probably doing photosynthesis is 2 or 4 hours longer than just the max 3 hours. Plus 2 hours would be 5 and that's OK but it could probably use more. Plus 4 and your at 9 hours and that's plenty.

 

[Bpb]

Personal opinion but I’m inclined to say those numbers are right on the money in terms of output. Off colors can just as easily be a result of imperfect nutrient/trace profiles, nutrition, instability of major elements, or just the wrong spectrum. I know in my own tank, simply switching from 14,000k bulbs to 20,000k bulbs caused a dramatic shift in color of many different sps. Nothing else has changed. Just the light color. Less cyan and red has caused a reduction in development of many pigments that were once present. PUR is higher, growth is definitely faster, but some are producing less reflective pigments due to weaker wavelengths that cause those to be generated

 

[Donny41]

Ok well I played around with the lights a bit this morning. First thing i did was spread the LEDS out about 2 inches further apart. Tested par after reducing the LED intensity and was able to get slightly more even distribution. Biggest pain is having a 24 in t5 over the 36 in tank (decided on purchasing an additional LED over a new t5 fixture when I upgraded tanks) here is what I seetled on.

 

[Donny41]

Next I am going to map out a few more with higher LED percentage so I can increase those if needed after I return the par meter but right now its too nice a day to spend anymore time doing that so that'll be tomorrows morning project.

 

[Bpb]

Just sharing a personal opinion but there are a couple ways to handle a hybrid approach. Treating your T5 as your mid day pop, and your leds as your long photoperiod primary color generator.

Or....treating your T5’s as diffused sky lighting for the longer period, and the leds almost like metal halide pendants. Your spotlight sunlight.

I feel like most people follow the first approach. In theory I like the second approach better. I would use an even mixture of ati blue+ and coral+ and have those bulbs come on first and turn off last. That’s the long photoperiod. And I would use the leds for the bright light mid day and run all channels maxed. Or at least all channels even and set the intensity to achieve 400-500 par for a short 4-6 hour blast. And let the gentle diffused t5’s run the lower par 12 hour photoperiod. Personal opinion. Kick it to the curb if that sounds awful. That in mind I also don’t care for the super blue smurf water look