Par Meter Readings Confusion

[rffanat1c]

So I rented an Apogee MQ-510 from BRS and got it today. I am running a 180 with three Gen 2 Radion's at 60% mounted on the RMS Track (8" off water) using the Ecotech Coral Lab LPS/Softie program. My dkh is 10, calc 480, mag 1300 or so, nitrates and phosphates not detected on test kits (Stopped GFO about a month ago after only running it for about 3 weeks), sg 1.026, temp is 78.

I was running my lights at 50% on the radiant color program and noticed my frogspawn and hammer at the bottom of the tank were beginning to fade in color. I bumped it up to 60% and coloration is coming back but this is also timed with installing dosing pumps maintaining my dkh and calc whereas before I was manually dosing weekly. A brand new war coral on the bottom of the tank is already bleached after one week.

Bottom line is I am surprised at what readings I am getting!! At 20" deep, I get a consistent about 50-60 par. At 6" I get around 60-70 and at 10-12" I am getting 100 par. Up top just under the water I see around 300 par. How is my coral growing and bleaching all at the same time with these numbers?? My torch is thriving in the 100 par range and never started to bleach. Can anyone help me make heads or tails of these readings? I want to dial everything in correctly before I have to send this thing back.

Thanks.

[alton]

0 Nitrates and Phosphates is never good, corals need food. My Frogspawn has done well in PAR levels from 75 to 400 and nitrates from 2 to 80.
The first two pictures are led at 100 to 200 PAR, the third picture is under metal halide around 400 par

[rffanat1c]

Originally Posted by alton

0 Nitrates and Phosphates is never good, corals need food. My Frogspawn has done well in PAR levels from 75 to 400 and nitrates from 2 to 80.

The first two pictures are led at 100 to 200 PAR, the third picture is under metal halide around 400 par

I am not shooting for 0 by any means. They are there since I have film algae every other day.


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[alton]

If your algae is cleaning your water too much then your corals may suffer. Also why not raise your par levels up. Just curious how old are your lights?

[Tripod1404]

I couldn't keep my nitrates and phosphate above zero as well. It can sometimes be an issue for some tanks. I tried doing them for some time but amounts required become infeasible and it cause the values to fluctuate(which seemed to make corals less happy). So for the last 8 months or so, I let them drop to zero and I also let alk drop to NSW levels of 6.6dKH. My corals are as happy as they have ever been and colors become far more intense.

[mattgumaer]

I had your exact tank and setup, a 180 with three Radion Gen 2 pros. Mine were hung about 9 inches off the water, which was as high as I could get them in the space. I had good softies, LPS and 'easy' sps but couldn't keep acropora. I was turning my lights up and down, with some corals improving and others suffering with each move. I bought a par meter and discovered, the intensity of the lighting in various areas of the tank was vastly different. Turning up the lights to get good par in deep areas not directly under the pucks was cooking coral right up top under the pucks. Turning the lights down would improve the coral right under the pucks but, other corals not right under the pucks appeared to suffer from the lower par.

My solution was add 4 5-foot t-5s and turn the Radions down. I now have much more even lighting and do not feel the need to constantly tweak up and down.

Other potential solutions include: 1) raise the Radions higher above the tank to even out the lighting; 2) add the optional diffusers (which I have also done) which should help some; 3) supplement with t-5 or other more even lighting (like LED strips); and/or arrange your rockwork so the 'valleys' are directly under the pucks and the 'peaks' are further away. You could also add more Radions but, this would be the most expensive solution.

Unfortunately, with 3 Radions over a 180, 8 inches off the water, I think you're going to have a difficult/impossible time getting consistent lighting across the tank but, that is just my opinion. Good luck.

Matt

[rffanat1c]

Originally Posted by alton

Also why not raise your par levels up. Just curious how old are your lights?

They were purchased used and were made in 2013. I can raise them but the confusing part is how am I bleaching a war coral with 50 par and why is coral that lots of places say demand 150-250 par growing with 50-60 par?

I had no issues on my 90 and I was only running two XR15 Gen 3's. I could grow anything in that tank but it was "dirtier". Maybe I will up feeding to once a day. I place my coral knowing the corners and bottom is darker. I have a montipora spongodes that is sitting in about 115 par and is growing.

I know that with all color channels at 100 there would be more par. Running the Coral Lab my ecosmartlive shows "35% intensity" at 60% brightness. You just always heard how powerful these lights are and these readings seem weak at 60%.

[mattgumaer]

A couple of addition thoughts. I have the Apogee 520 (usb) meter. My sensor is very sensitive to the angle of the sensor relative to the lights. It seems like tilting the sensor even a few degrees can significantly impact the reading. For readings in open areas of the tank, I tilt the sensor around a bunch and take the highest reading. For areas in the rockwork, this is more difficult. So, if things like your war coral are in the rocks and/or near the bottom, it may be harder to angle the sensor towards the lights. I don't think its possible that you're bleaching anything with 50 par.

Second, I think, in general, lighting should be consistent with nutrient level. High light and low nutrients may cause problems, particularly with corals that want to grow fast under high lighting.

Matt

[rffanat1c]

I noticed the angle thing while using this. I definitely want to up my nutrients, but carefully. Just got done dealing with hair algae!


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