Any tips for using a par meter on a tank with a lid?

[mike550]

I’d like to rent a par meter to check lighting in my tank but have heard that this can be tough when the tank has a lid or covers. In reviewing the BRS rental it comes with a stick to hold the sensor which would be great if my tank was open top — and apparently the stick floats. So it can be hard to keep the sensor pointed up.

Would appreciate any suggestions. Thanks in advance!

 

[oreo54]

Are you talking glass top?
Egg crate?
Screen?

Each will have a slightly (or larger) difference in an "error correction"
Worst is black hinges on some glass top types.

Generally consider about a 10-20% loss depending on the material and condition.

Par rating through lid?

so i cant find any information on this, maybe someone can help me. Saw a BRS video today about par rating loss through a mesh screen top which claims you lose between 2.5%-6% par rating depending on lighting. This is a very minimal loss and is acceptable in my opinion, however i was wondering if...

www.reef2reef.com

That said 200 vs 170 (15%) "PAR" isn't really significant.

Egg crate is prob the worst..but arguable. "tests" are all over the board.

Eggcrate for focusing light

Did anyone else try putting the eggcrate over their tanks to focus the light the way Anthony Calfo suggested? I did this - tried it both ways - and see no difference. If anything, I think the light is more diffused. Again, tried the eggcrate both ways since 1 way is supposed to diffuse while the ...

wamas.org

 

[Spieg]

Personally I don't like solid covers on a reef tank (filters out some light, accumulates algae/salt creep, and limits gas exchange). If you absolutely have to have them, then it will be tough to measure PAR accurately... not sure I would even bother with a PAR meter in this case.

 

[oreo54]

Personally I don't like solid covers on a reef tank (filters out some light, accumulates algae/salt creep, and limits gas exchange). If you absolutely have to have them, then it will be tough to measure PAR accurately... not sure I would even bother with a PAR meter in this case.

Well.. Knowing you have 200 PAR plus/minus is better than ??? par.

 

[Spieg]

Well.. Knowing you have 200 PAR plus/minus is better than ??? par.

Agreed, but is it worth spending the money for a meter? You can get a ball-park guess just by the light type and water depth. I'd contact the light manufacturer for more info.

 

[mike550]

@oreo5457 and @Spieg -- sorry for the confusion. My aquarium cabinet also has a canopy. The canopy tilts back so I can access tank to feed and service. But the lights are attached to the canopy. So basically, for the lights to be pointed "down" the canopy needs to be closed. So there isn't a way for me to hold the sensor wand and close the canopy. Hope this makes a bit more sense.

 

[Spieg]

@oreo5457 and @Spieg -- sorry for the confusion. My aquarium cabinet also has a canopy. The canopy tilts back so I can access tank to feed and service. But the lights are attached to the canopy. So basically, for the lights to be pointed "down" the canopy needs to be closed. So there isn't a way for me to hold the sensor wand and close the canopy. Hope this makes a bit more sense.

Thanks for the clarification. Many canopies are open in the back for ventilation. Maybe you can reach the tank from that way?

 

[mike550]

Thanks for the clarification. Many canopies are open in the back for ventilation. Maybe you can reach the tank from that way?

Great thought. Unfortunately the back is close to a wall. What I’m trying to find out is how people are setting up the Par meter in a tank with a canopy top. I can’t be the first one to try this (?)

Im guessing I can set the sensor in the sand bed for bottom measurements. But trying to think about how to set the sensor upright if it’s on the rock.