T5 Mounting Height

[Agape1love4ever]

Hello everybody. I need help with figuring out how high to mount a T5 fixture. It’s a six bulb 60 inch t5 fixture. I have them mounted in an open canopy about 16 1/2 inches above surface of water. I used my par meter and measured the bottom of the tank and it is around 240. I want it to be lower, but it also doesn’t make sense to me how I could be so high up and yet still have such a high reading 2 feet beneath the water. Can anybody relate or give me some info about what I’m doing wrong? I am running four ATI blue pluses, one coral plus and one true actinic. It seems like every time ive raised up the lights I’m only losing about five par at a time. It doesn’t seem like I should have to be this high up and still be so high in par.

 

[Agape1love4ever]

BTW I have a six foot by 2 foot 130 gallon tank if that helps at all.

 

[Big E]

I would check your par meter...........those numbers are not right from my experience.

Generally if you run that fixture about 8-9" from the water surface you should get about 200 at the bottom and 300 mid level

 

[Agape1love4ever]

@Big E - thanks. I’ll have to look into the par meter issue. All the research I’ve done lines up with what you say, but then I have this meter saying that I’m still around 240 at the bottom of my tank. It’s an Apogge PQ- 510 meter which you monitor from an app on your phone instead of a conventional par monitor. Maybe I have to recalibrate.

 

[Agape1love4ever]

So what I found out concerning the par meter is that the certain par meter that I have is only meant for LED lights. Which is unfortunate since I have a second tank with T5s.

 

[Uncle99]

Best would be a PAR at the surface of 300 ish, mid way down 200 and bottom of 100, 50-70 in the corners.

I think you got to go higher if you can.

 

[Agape1love4ever]

So I talked to the customer service representative from Apogee and he said that the par sensor I have works for LEDs and T5s. So at 16 1/2 inches above the surface of the water my lights are putting out 240 on the Sandbed on a 2 foot tall 6 foot long tank. I’m just confused about it because I’m reading other threads, and they all say they mount theirs at 9 inches all the way down to 4 or 5 inches which would completely annihilate most of my corals. I don’t understand it.

 

[Agape1love4ever]

By the way, the first representative I spoke to was from Bulk Reef Supply who said that my type of par meter is only for LEDs but the representative I spoke to at Apogee said that the sensor was good for all light systems.

Just wanted to post this comment in case anybody was confused about my contradictory statements.

 

[Big E]

What brand fixture are you running?

I don't doubt the Apogge PQ- 510 is fine for your application but it doesn't take into account that the probe may be malfunctioning.

 

[Agape1love4ever]

@Big E - it’s a homemade canopy with 3 - Miro- 4 retrofit kits.

 

[Big E]

If you mean the LET kit, then take your par meter and put it about a 1/4" from the bulb in the center of the tube. You should get a reading in the 800 range.

This should be the reading with a Blue+ or a Coral+

I'm not familiar with the phone app type setup, but if there are options for T5, Led or whatever make sure you have it set correctly.