Need help with a Par38 bulb

[MiracleFish]

I feel like Ive been burning the crap out of my corals. I had my bulb about 8 inches away from the water level, until I moved it to 14 inches and dimmed it 3/4.

My candy cane coral's skin was starting to recede and my hammer was starting to lose a head. Is the positioning on the bulb okay? (14") Is it okay if I dim the bulb from that height? Its a shallow tank, only 8" deep. No SPS, just LPS and softies. tank parameters are fine.

Calcium: 460ppm
dkh: 7ppm
phosphates: 0ppm
Nitrates: 0ppm
Nitrites: 0ppm
Ammonia: 0ppm
Magnesium: 1250ppm

I have a hard time reading my ph. I use the API pH test, but it looks purple under natural light, but since I don't have the sheet, I use the computer generated chart and looks more like 7.8 than 8.0 because of the white screen.

[MizTanks]

Raising it is fine as is lowering the intensity. Don't see the need for doing both.
It is best to use daylight when reading test kits.

[MiracleFish]

Raising it is fine as is lowering the intensity. Don't see the need for doing both.
It is best to use daylight when reading test kits.


Is that distance fine for all the corals?

[Raoul5Duke]

Distance above the water, intensity and how far away from dead center will all affect the par. Different corals need differnet PAR levels. Here is an article that contains PAR plots:
http://blog.captive-aquatics.com/captive_aquatics/2010/08/ecoxotic-par38-led-spotlight-review.html

I used to use them on a frag tank and 14" sounds more than reasonable. Did you acclimate the corals to the new light?