Question on light spread

[ghostandhyde]

Hey all, I am using an mq-510 par meter. After watching my lps struggle on the sand bed, I took a par reading. Why would my par be 255 center of the tank on the sand and 220 center of tank on the rock? The tank is a RedSea p650 with 3 Radion blues.

 

[EeyoreIsMySpiritAnimal]

My first thought is that the spot you're measuring on the sand is receiving full light from all 3 Radions while the spot on the rocks is not...

Also, is the flow completely off when you're measuring?

Edit: beautiful tank, btw

 

[ghostandhyde]

Thank you! I thought the top of the rocks would also get par from a combination of the lights too. Just seemed odd that the sand bed would have more par than the top of the rocks at the center of the tank. The water flow was off while taking measurements. I’ve used t5s for many years and Never encountered this scenario.

 

[EeyoreIsMySpiritAnimal]

LEDs focus light differently than T5s and there are definitely "hot spots" where they overlap.

 

[ghostandhyde]

LEDs focus light differently than T5s and there are definitely "hot spots" where they overlap.

Thank you. Just picked up a few diffuser To see if they help

 

[hart24601]

As stated it can be the rock is high enough that it doesn’t get the overlap from other fixtures. Also possible if measurement is close enough to the glass it’s getting increased par from the reflection off the glass. That can add up to a surprising jump in some cases

 

[ghostandhyde]

As stated it can be the rock is high enough that it doesn’t get the overlap from other fixtures. Also possible if measurement is close enough to the glass it’s getting increased par from the reflection off the glass. That can add up to a surprising jump in some cases

My par was 300 next to the glass