how are these numbers?

have a 90 cube... noticed a plate i had in the center was browning when it used to be a nice green... here are my readings...

ca-410
mg-1340
kh- dKH : 9.3 3.31 meq/L
Ph-7.8

those don't look bad. I always keep track of Ammonia and nitrates too. Do you have tests for them?

Hmmm...pH looks a little low. In general, to keep pH around 8.2-8.4 is recommended and suggests the best result for coral growth. Is the coral near anything else, like another coral, or close enough to something with sweeper tentacles? I lost an acro colony to a tube nem because it's tentacles extended twice their size at night and totally zapped the whole acro colony!

can you shoot some pics for us too? I've never really noticed lps corals browning much before, usually they just get pale if not enough light..... It could be anything at this point

Ammonia is at 0.25 or below. Nitrates are around 10 mg/L

Here's a pic of the setup. Plate in question is in the center. Seems the corals are just not as viberant as they could be.

Here is a shot from about 2 months ago.

My first thought was less intense light causing the browning, but it doesn't look like the light is low. That is a stumper!

its probably the nitrates that is giving you the "slight" browning ..... oorrrr, havent asked this yet - how old are your bulbs?? If they are 9 months + they could be just to the end of their lifecycle.. I get some browing in my tank at 9 months + on my bulbs...

I think bulb is around 6-7 months. Radium 20k 400w MH

Yea I would say the light is probably due to start fading a little if not already

+1 on replace the bulb. All your other parameters look good, so that is the next thing to check.

Originally Posted by MikeM

I think bulb is around 6-7 months. Radium 20k 400w MH

i've noticed my MH bulbs starting to loose their luster at 6 months.... it is really hard to hold out for the year!!! hahaha

have you read some of the articles from sanjay joshi about how PAR output changes in MH bulbs over time???

here is a couple of good reads too: Spectral Analysis of Metal Halide Lamps Used in the Reef Aquarium Hobby Part 1: New 400-watt Lamps
Spectral Analysis of Metal Halide Lamps Used In The Reef Hobby — Part 2

Is this the first time its "browned"? how long have you had it?

thanks all for the input... i am currently trying to get a tank i recently purchased off a fellow member to fit in a space in the kitchen on a wall i thought would be perfect... would have been if it were 2 inches more room on the wall. trying to convince my wife to remove a cabinet to fit it ;-) i will be replacing the bulb but was holding off to see if I was changing setups for lighting... currently running a 400 watt and might go to 3 250's thanks for looking all and the plate has been in tank over 7 months.

Pics would help because I am wondering if...
-It's LOOSING green revealing brown (which would be a sign of low light)
Or
-If it's gaining brown making it appear that it's changing colors, when it's actually gaining color, (which would indicate it's getting back previously lost zooxanthellae, thus getting healthier)

For example... (And let me preface by saying I pulled these off the net, they aren't my own pics)

But the first pic, where ironically, when he posted it everybody said "Awesome coral" and "Nice find", when it's not a nice find- it's a typical green ric with no zooxanthellae... Pretty, but stressed none the less...


Then another, more healthy, green ric. One could assume it's turning brown, but it's not turning color, it's adding color. Making the green look well, less green...
But these pic are from stressed and not happy- to a more happy coral.

(I wouldn't go so far as to say the first one is "sick" as I read so often, cause it's way to easy for a coral to regain it's symbiotic algae, so I prefer "stressed")

excellent point tizzo..........and GREAT visuals too!! that's something that all of us need to keep in mind too - - we can sometimes be dazzled by the pretty bright colors.........thanks!

Numbers look fine, PH is little lower the typical norm but I could never keep mine at 8.2 and it did just fine.

I would like to know what the nitrate and phosphate readings are.

Ammonia and nitrite readings are also important but if it is a established aquarium and you have done anything drastic there probably ok but still good to test for them.