PAR settings

[Cluanar]

So I have had my tank for about 17 months and although numbers have been good I cannot get corals to grow and in many times survive.

I have two (2 puck ) AI vega lights and even and w 5 all blues 20 it looks extremely bright.

I decided to rent a par meter and at the highest point of the day did a measurement and found that the bottom had a 15 par and the top 30 par.

I could not have imagined it would be that low since to the eye it was so bright.

I guess then I need to satisy the par needed despite what the eye wants?

Thanks

[AlexR]

Originally Posted by Cluanar

So I have had my tank for about 17 months and although numbers have been good I cannot get corals to grow and in many times survive.



I have two (2 puck ) AI vega lights and even and w 5 all blues 20 it looks extremely bright.



I decided to rent a par meter and at the highest point of the day did a measurement and found that the bottom had a 15 par and the top 30 par.



I could not have imagined it would be that low since to the eye it was so bright.



I guess then I need to satisy the par needed despite what the eye wants?



Thanks

I think you just found your problem yourself and also answered it.
That PAR is absolutely low for mostly all living things in a reef tank.

[smilinteddy]

I remember seeing a BRStv episode on lighting where they mentioned that especially with LEDs it's extremely difficult to judge PAR level by eye. They showed side by side shots of a tank lit with LED's set at 30%, 60% and 100% intensity and they were virtually indistinguishable. Judging LEDs is hard.

It's also good to remember that PAR and brightness to the eye don't necessarily correlate. Just because something looks brighter doesn't mean it has a higher PAR, and the relationship between perceived brightness doesn't necessarily translate to an equal relationship in PAR.

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[AlexR]

Originally Posted by smilinteddy

I remember seeing a BRStv episode on lighting where they mentioned that especially with LEDs it's extremely difficult to judge PAR level by eye. They showed side by side shots of a tank lit with LED's set at 30%, 60% and 100% intensity and they were virtually indistinguishable. Judging LEDs is hard.

It's also good to remember that PAR and brightness to the eye don't necessarily correlate. Just because something looks brighter doesn't mean it has a higher PAR, and the relationship between perceived brightness doesn't necessarily translate to an equal relationship in PAR.

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Good point. Before I checked par I always thought my lights weren’t bright enough. Then when I tested I found out they were way too bright and I was nuking my corals...
Unless you have some super vision sense it’s not possible to measure with the eye.

[Cluanar]

Originally Posted by AlexR

I think you just found your problem yourself and also answered it.
That PAR is absolutely low for mostly all living things in a reef tank.

So I will test this myself but what effects par the most , whites or blues.

[AlexR]

Originally Posted by Cluanar

So I will test this myself but what effects par the most , whites or blues.

Just like most things in this hobby. This answer can be complex. And not something I would be fully qualified to answer.

Here is a good resource.
http://www.americanaquariumproducts....ting.html#par2

[smilinteddy]

This video breaks things down pretty well and I like how it explains the difference between PAR, PUR, brightness, etc.

https://youtu.be/Sqg884X_lZ4

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[Cluanar]

Originally Posted by AlexR

I think you just found your problem yourself and also answered it.
That PAR is absolutely low for mostly all living things in a reef tank.

Curent settings and par

White 20%
REd 4%
Green 7%
Blue 75%
D-Blue 75%
Royal 75%

Par at water level 270

Mid 120

Sand 30-50

Seems too low still but looks super bright in tank.

[smilinteddy]

Originally Posted by Cluanar

Curent settings and par



White 20%

REd 4%

Green 7%

Blue 75%

D-Blue 75%

Royal 75%



Par at water level 270



Mid 120



Sand 30-50



Seems too low still but looks super bright in tank.

How high are your lights hung off the water?



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[Cluanar]

Originally Posted by smilinteddy

How high are your lights hung off the water?



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10 inches in a 90 gal 31 in from sand bottom

Here is a pic that shows how bright the tank looks.

[Cluanar]

Originally Posted by Cluanar

10 inches in a 90 gal 31 in from sand bottom

Here is a pic that shows how bright the tank looks.

so going from the low par numbers i was at I should probsbly acclimate to the new numbers at 50% over 5-7 days?

[Cluanar]

Originally Posted by Cluanar

so going from the low par numbers i was at I should probsbly acclimate to the new numbers at 50% over 5-7 days?