T5 lighting

[Rmckoy]

Back to the same drawing board .

8 bulb t5ho 54watt bulbs ( 48” )

there is a formula somewhere to calculate how much par loss for every inch depth ?

i have my fixture roughly 5”-6” above the water .
top of the rocks are about 12” below the water .
is there a way to guess or estimate par directly below the fixture ?

Brs apparently did a calculation or experiment on how much par is lost at different depths ?

 

[EeyoreIsMySpiritAnimal]

Back to the same drawing board .

8 bulb t5ho 54watt bulbs ( 48” )

there is a formula somewhere to calculate how much par loss for every inch depth ?

i have my fixture roughly 5”-6” above the water .
top of the rocks are about 12” below the water .
is there a way to guess or estimate par directly below the fixture ?

Brs apparently did a calculation or experiment on how much par is lost at different depths ?

Can you rent or borrow a PAR meter? That will give you better piece of mind than someone else's experiment...

 

[Rmckoy]

Can you rent or borrow a PAR meter? That will give you better piece of mind than someone else's experiment...

Ill
Look into it .
there are too many variables to say each t5 bulb at 6” above water provide x number par ?

 

[EeyoreIsMySpiritAnimal]

Ill
Look into it .
there are too many variables to say each t5 bulb at 6” above water provide x number par ?

Short answer, imo, yes.

 

[MasterOfNone]

Check some light manufacturer websites. Some of them publish charts of approximate PAR values at varying depths. These could give you an idea of what you might see in your tank.

 

[nereefpat]

I don't know of a formula. There's probably a complicated way to calculate it, involving what bulb, what ballast, distance between bulbs, reflector type, shield, age of bulb, densities of air and saltwater....yuck.

I can tell you that unless your tank is deeper than 30", you can grow anything anywhere with 8 bulb T5. Or are you more worried about cooking the stuff on top? PAR also isn't equal across lighting types, where 500 PAR from a black box vs 500 PAR from T5 will do different things. I've actually never seen any evidence in my tanks that something was overlit with T5, even on the top of the rocks. Now, I wouldn't mount Cyphastrea up there, for example. It *seems like, to me, light acclimation with T5 isn't really an issue.

 

[IslandLifeReef]

The other thing you could do is look at the **** R2R Par Database **** for you fixture or a fixture similar to yours and see the numbers they came up with.

 

[Rmckoy]

I don't know of a formula. There's probably a complicated way to calculate it, involving what bulb, what ballast, distance between bulbs, reflector type, shield, age of bulb, densities of air and saltwater....yuck.

I can tell you that unless your tank is deeper than 30", you can grow anything anywhere with 8 bulb T5. Or are you more worried about cooking the stuff on top? PAR also isn't equal across lighting types, where 500 PAR from a black box vs 500 PAR from T5 will do different things. I've actually never seen any evidence in my tanks that something was overlit with T5, even on the top of the rocks. Now, I wouldn't mount Cyphastrea up there, for example. It *seems like, to me, light acclimation with T5 isn't really an issue.

The lights are only 6” above water line .
Is that too close ?

 

[nereefpat]

The lights are only 6” above water line .
Is that too close ?

I keep mine higher, maybe 10-12", so I can work in the tank. Some people do set them basically right on the tank. I think you're okay. You may get some water spots on the light.

Are you worried about too much light? What are you keeping up top?

 

[Little c big D]

If the highest point of the rock is 12 inches than I don't feel 6 inches above the surface is bad.

 

[Rmckoy]

I keep mine higher, maybe 10-12", so I can work in the tank. Some people do set them basically right on the tank. I think you're okay. You may get some water spots on the light.

Are you worried about too much light? What are you keeping up top?

Top of my rocks is 13” below the water line .

 

[rtparty]

There are so many variables that will dicate the final outcome. What fixture? Is it properly cooled? What bulbs? Are they installed in the correct orientation? (If your fixture is cooled this matters)

Is your water super clear or slightly yellow or have a lot of organics floating around?

Sadly, there is no way to create a formula for PAR. With all that said, I have found overlighting with a T5 is almost impossible. Assuming proper placement of corals.

 

[Rmckoy]

There are so many variables that will dicate the final outcome. What fixture? Is it properly cooled? What bulbs? Are they installed in the correct orientation? (If your fixture is cooled this matters)

Is your water super clear or slightly yellow or have a lot of organics floating around?

Sadly, there is no way to create a formula for PAR. With all that said, I have found overlighting with a T5 is almost impossible. Assuming proper placement of corals.

It’s a old fixture . I’ve replaced the ballasts a few times over the years. .
bulbs are all ati
Staggered blue plus and coral plus .
Water is clear , but there is a fair bit of water movement on the surface which I assume would also effect par