Par meter question

[Addictedreefer87]

I recently bought a wet tested par meter from BRS. Just unboxed it and gave it a try. I run 4 hydra 26s over my 210 gallon tank with the ab+ full power schedule. My lights are 13 inches off the water. Water level reading was 250 par 30inches below on the sand bed I got a reading of 80-100. How is this possible with my lights basically turned up all the way. Is there something wrong with the sensor? Does anybody have experience with using a par meter? Am I doing something wrong?

 

[Dolphins18]

I have a par meter but it is a different one to the BRS one. They are all a bit of a PITA in my experience. When looking at your tank from the front, are your AI lights mounted horizontally or vertically?

 

[Addictedreefer87]

I have a par meter but it is a different one to the BRS one. They are all a bit of a PITA in my experience. When looking at your tank from the front, are your AI lights mounted horizontally or vertically?

Vertically. I did test directly under the light too.

 

[Dolphins18]

Vertically. I did test directly under the light too.

Gotcha, I am not sure if something is wrong with the par meter but I have a similar tank and lights (1x64 3x32), if that is the HMS AI bar try mounting the two middle ones horizontal and the outside ones vertical. May give you a bit more

 

[Bume]

That sounds about right to me, I have Hydra 52s over a slightly deeper tank (only 2 lights). Mine are 7 inches over the water and about 30 inches above the sand. My PAR goes from 850 at the surface, down to 200 on the sand. With 4 lights, you will have better spread and higher par in the middle 3 sections where the light "cones" cross over each other. I have a hotspot in the middle, where mine crosses over that shoots above 1000 par.

If you want higher par, you might try lowering them and/or adjust your spectrum.

BRS did a great video on those lights if you haven't seen it:

 

[Addictedreefer87]

I have a par meter but it is a different one to the BRS one. They are all a bit of a PITA in my experience. When looking at your tank from the front, are your AI lights mounted horizontally or vertically?

Vertically. I did test directly under the light too

That sounds about right to me, I have Hydra 52s over a slightly deeper tank (only 2 lights). Mine are 7 inches over the water and about 30 inches above the sand. My PAR goes from 850 at the surface, down to 200 on the sand. With 4 lights, you will have better spread and higher par in the middle 3 sections where the light "cones" cross over each other. I have a hotspot in the middle, where mine crosses over that shoots above 1000 par.

If you want higher par, you might try lowering them and/or adjust your spectrum.

BRS did a great video on those lights if you haven't seen it:

That's the thing I'm at 300 par at the surface I don't even get 800 unless it's out of the water 4-5 inches under the led.

 

[Dkmoo]

Thats completely normal - r u familiar with the inverse square relationship of distance and light? The gradient changes a bit in different medium (air vs water) and internal reflection gives your bottom a lot more extra light than the formula shows but what you just described sounds about right.

 

[Addictedreefer87]

Thanks everyone. I'm going to lower the lights a little and tweak some things here and there. I appreciate all the input.

 

[Dolphins18]

Thanks everyone. I'm going to lower the lights a little and tweak some things here and there. I appreciate all the input.

I run mine at 10" if that helps!

 

[Addictedreefer87]

Just to update the thread. I ended up ordering a t5 hybrid and it helped achieve the numbers I was going for. 1st pic is of just the hydras ab+. 2nd is hydras ab+ and t5s.