Need LED Lighting Advice

SMSHAPERO · Nov 17, 2020

I am new to this forum and have been keeping salt and freshwater aquariums for years. I just switched to LED lights for my 37-gallon reefish tank. I have a large damsel and a bunch of mushroom coral. The coral was doing great under my T-5 Fluorescent lighting. About a month ago I purchased an Ocean Revive Arctic T247-B Full Spectrum Dimmable LED Aquarium Reef Light. The aquarium is 21.5" deep. The light is suspended 5.5" above the rim. Since installing this light my mushrooms have not opened completely. The seller (a company that sells coral and anemones and say they use this light) told me to put intensity for blue channel at the lowest setting (1) and white at 5 (out of 100). I have left it there for 2 weeks with little change. I have tried LEDS before and gave up. This is the most expensive light I have purchased ($170). Any advice would be appreciated. I never had any issues with the T-5. I have attached pictures.

Doctorgori · Nov 17, 2020

Broken record but: Par meter my friend. Shrooms can get pizz’d at strong light if they are used to low. I got shrooms in decent par but they grew up there ...
5” might be a lil close, whats the spread looking like?
Maybe crank up blue to 100% , white to say 10% and mount higher...verify with par meter -.I like12K personally

SMSHAPERO · Nov 17, 2020

Thank you for your advice. The distance from the mushrooms to the light is 25". Spread is good as the mushrooms are directly under the center of the light. What should the PAR be?

oreo54 · Nov 17, 2020

https://cdn.shopify.com/s/files/1/0152/1876/9984/products/7_1294ab0f-4799-4854-91fd-2e04217225e9.jpg?v=1567265856

Hiw many and what wattage were your t5's?

SMSHAPERO · Nov 17, 2020

31 watt white, 31 watt actinic blue

kwirky · Dec 9, 2020

I've had negative experiences from white led, bleaching and death of spa when need even more light than mushrooms. Blue LEDs don't look bright to our eyes but they provide a lot of radiation for photosynthesis, which doesn't need the full spectrum (look up the spectrum requirements of chlorophyll).

If you can rent, borrow or buy a par meter, you'll have an easier time. 150par of light with the white dialed way back to 10% should be safe.

The blue LEDs are probably royal blue, which puts out a lot of radiation in a chlorophyll peak.

Raise your lights up to about 8", and start at white 10% and blue 50%, because 100% might cook your coral. Brown Coral means too little light and you can increase the blue 10% 2x per week until you barely see the brown lessen or they open a bit more a day after an increase. If you see anything turn pale, turn it down 10% and give it a few weeks before trying again. Once you see them respond positively to an increase/decrease, don't touch it for at least two weeks. You're at a sweet spot.

Once you've been at that sweet spot for a month, if you feel like increasing it to get more color, increase just the blue, and only a small amount, 10%. Check on your Coral multiple times over 48 hours and if they respond negatively, put it back right away.

LEDs have drastic peaks of spectrum, compared to t5ho, so it's easy to get the spectrum wrong and 200 PAR at the wrong spectrum can give you problems like you're describing. Yes, your t5ho fixtures are easier to use and if you still have them and they're a suitable size for the tank (you didn't change tanks, too?), you may actually have better results switching back to your old t5ho and leaving led behind. There's no shame in it, t5ho is still a relevant technology.