Switching to LED from MH, should I match PAR?

[mic209]

So I'm thinking about switching my 150w MH for a hydra 26 or a XR15. When I put the LEDs over my tank should I set as close as possible to match the par readings I got from my MH? Or should I start a little lower? I'll be using apogee mq-200 par meter.

 

[Eckolancer]

Par is not a great way to measure leds. Start about 50% watch polyp extension for a few days. Increase upto where polyps don't look like they are stretching to bad.
Now what I have done with all corals that come into my tank. I place them on the bottom for a few days then mount them where they will be. I run my Kessils at 100% for 14 hours. They go from blue to white to blue. Did the same thing for years on my diys. Still never lost a coral to leds like some say happens. Good luck.

 

[mic209]

Par is not a great way to measure leds. Start about 50% watch polyp extension for a few days. Increase upto where polyps don't look like they are stretching to bad.
Now what I have done with all corals that come into my tank. I place them on the bottom for a few days then mount them where they will be. I run my Kessils at 100% for 14 hours. They go from blue to white to blue. Did the same thing for years on my diys. Still never lost a coral to leds like some say happens. Good luck.

Thanks for the advice, this my first time I've heard to use polyp extension to setup lighting. Don't you think there are other factors that affect polyp extension? What if somebody didn't have SPS or LPS corals?

 

[Eckolancer]

I would just keep an eye on the corals make adjustments but give it sometime to show changes. If you are seeing say SPS with tips burning off then turn them down a little. I have never see this in my tank yet. I still think if a coral is showing signs of bleaching out under leds it is from lack of light.
All of that said is based on lighting only. If you have issues with your corals under MH it will continue with leds. Like algae, alk, cal, mag swings, ect...

 

[TJ's Reef]

If you have access to a PAR Meter certainly use it. Though not as accurate on measuring LED output I'd still take measurements on MH and then try to adjust LED's to approximately 75% of that reading. LED's have very little 'garbage light' that's inherent with incandescent style lamps and fully registers on PAR Meters so will skew readings to the shy side. LED's have a much higher percentage of PUR especially in the Blue 450-460nm range and why it is so easy to overdue it. Typical starting points are around 45-55% Blue Channel(s) and 20-30% White Channel. My Broad Spectrum DIY array is mixed emitters on all circuits and fully acclimated for 3 years only run approx 45% without optics. I get 250-350 PAR throughout entire tank.

Cheers, Todd

 

[Eckolancer]

Here is a par reading without optics on my tank DIY running 100% on all leds. 96 leds in total on a 4 foot tank 20" deep

 

[Eckolancer]

Current shot with kessils but need to borrow the par meter again.

 

[ReefLEDLights]

Photohinibition starts around 350-500 PAR depending on the coral.

Sanjay recommends a minimum of 100 PAR on the bottom of the tank. I like 200 for SPS, Clams and Carpet Anemones.

Personally I feel a 150 watt MH equivalent is weak except for a nano tank.

The Best SPS tanks I've seen use 400 watt MHs or their Cree LED equivalent.

Although this is above the lighting needs for corals close to the surface the extra light causes SPS corals to produce desirable pigments to reflect the extra light.

Starting at 75% intensity from MH is not a bad place to start. It really depends on the MH and specific type of LED. A MH Radium I would be OK with 80-90%. A 10K XM maybe 65-75% as the XM has more yellow than our LED fixtures.

Bill

 

[hart24601]

Here is my tank with PAR numbers:

 

[TJ's Reef]

Hart, that is AWESOME thanks for posting it up here. Incredible amount of useful information in a single image.

Cheers, Todd

 

[hart24601]

I'm happy you found it useful! I have been very pleased with my reefbreeders.

 

[ReefLEDLights]

hart24601

You have a problem..

I was growing the same corals under 400 watt MH and now LEDs...

Be ready to donate or sell 5 gal salt water bucket sizes of those corals in a couple years.

Recently gave one Euphyllia to the Shedd that barley fit for transport.

Congrats on a nice looking tank.

Keep us posted on growth.

Bill

 

[hart24601]

We all have a problem, haha. I have a biocube 14 that I have to frag weekly it seems... The lfs and reef club seem to like it! That's one reason the biocube is mostly sps now, I get too excited and lps need too much space for stinging! I'm trying to keep my build thread updated with growth...

 

[Eckolancer]

Hart that is nice looking tank and great par reading example.

 

[mic209]

Here is my tank with PAR numbers:

That's impressive, but I wasn't looking for par numbers. Nice tank BTW.

 

[NanaReefer]

That's impressive, but I wasn't looking for par numbers. Nice tank BTW.

You did ask for par! Both in your title and first post.

 

[hart24601]

That's impressive, but I wasn't looking for par numbers. Nice tank BTW.

Sorry, guess I misunderstood, I thought you did want PAR numbers. My idea was to show what type of coral live in my tank under what PAR level for LEDs so you could see for yourself since you hear that LEDs measure differently from MH.