Montipora changing color

I have 3 separate sections of green plate montipora from 1 little frag I purchased a year ago. It had been growing well, with bright green color. About 2 weeks ago they each turned a brownish peach color, but still have bright green (sorry don't know name) little mouths(?) covering them. No new coral in a while.

All other coral in tank look fine; acropora, zoa/paly's, mushrooms, millepora, bird's nest... and I have seen some growth on one of the acropora.

Any idea's on possible cause?

Tested last night:
Ammonia: 0
PH: 8.0
dkH: 8.3
nitrite: 0
Nitrate: 2
Phosphate: 0
calcium: 400
(that's all the test's I have)

I did use Seachem Reef Buffer to try and raise PH after testing.

I do have a growing problem of algae on the sand, rust color with some algae strands. Green short hair algae growing on rock right in front of Koralia's. Rust color algae on one section of rock at the far right of tank facing side glass.

 

In the wild, once they reach a certain size or maturity (I forget which one), they turn brown. This normally takes a few years. One way to prevent this is to frag your monti. This is why I will never purchase a name brand monti.

What is your lighting situation? Type, age of bulbs, time period they are on.

 

well t sounds like you have a nutrient problem beginning. I know you tests state low levels but due growth of algae is proof. Alot of times the algae uses up the nutrients to make the problem. I would look at what you are feeding. If feeding alot of frozen cubes, make sure to rinse well before feeding. Thats the most common source of PO4. Also, what equipment are you running? I highly suggest GFO or some other form of PO$ remover. That would be my best guess as to why it is browning. Weird though it wasn't your acro's first. Yellow and Green SPS corals are the first to react to excess nutrients.

 

I did not know that.

 

I forget which magazine it was in, but there was a huge article on that topic.

 

I've seen some Idaho grape and red caps that were 2-3 feet across on other forums.... I HAVE NOT however seeen a green monti cap that big.

 

I have fragged it a few times. 6 T5HO bulbs. It did start after I took out an old Current white bulb, and and replaced with a ATI Aquablue+. (Coincidence?) 6-8 months old for others.

No GFO or PO. I did have a BAD hair algae problem in my old tank. Switched to this tank about 2-3 months ago. That tank had a canister filter, no sump and a HOB skimmer. Now have sump/fuge (deep sand bed, cheato, mangroves), in sump skimmer.

Biggest piece is maybe 3"x5". Other two are much smaller.

 

That could be it. You went from a low PAR bulb to a high (~300) PAR bulb. You could try cutting down the time the lights are on so it can acclimate to the higher par. Montis don't need a huge amount of light and it is possibel you are burning it a little bit. You also went from a 10K bulb to a 20K bulb. This alone can make the corals look different, but it should just bring more green out.

 

personally, i think it is your nitrates and your phosphates that are present. you are reading zero because the algae is absorbing the phosphates right away. IME when these two are present coral color declines

 

great point. I have fund the blues, reds, and purples normally go first due to high nitrates. Completely forgot about that. Good call.