SPS Polyp Extension Problem

[irensing]

I have lots of different SPS and various other corals. My tank is a 29g bowfront with a backpack wet/dry with built in UV and protein skimmer. I have a 250W 10000K MH and 2 65W CF actinics. Most of my corals are doing phenomonal and multiplying out of control. From day one my Acros, Mills, and similar SPS never sent out feeder tentacles. I've even woke up to check them at night...nothing. They continued to grow and look healthy. I've tried moving them to different levels in the tank. Despite them being healthy and growing for months I noticed they are starting to discolor a bit on the underside of the branches where they don't get light. Is this normal (I didn't think so)? Is the lack of polyp extension taking its tole on the coral? I know these corals feed by photosynthesis. I also add zoo and phytoplankton. Is this lighting too bright? What is preventing the extension? Would the corals prefer a 15000K over the 10000K? Do I need to reduce the amount of time my lights are on? Right now I turn the actinics on for 2 hours, the MH and ACs simultaneously for 6 hours, and then the actinics for 1 hour at which time the blue LED night lights come on for a few hours. I'm cautious about changing things too much because my other corals are doing great. Thanks in advance for anyone with advice.

Other hard/skeletal corals doing well in my tank are birdnest, stylaphora, montipora, blastomussa, Candy, Red plating Goniopora, Green Alveopora, and acan. My green Paulo tree is growing slower than expected. I just got a green polyp leather a few weeks ago. I love it...

 

[ccCapt]

What are your water parameters? Calcium, alkalinity, magnesium, nitrate, phosphate, salinity and temp.

From day one my Acros, Mills, and similar SPS never sent out feeder tentacles.

SPS corals don't send out feeders like many LPS do. Can you take a pic of some of the corals with no polyp extension?

Despite them being healthy and growing for months I noticed they are starting to discolor a bit on the underside of the branches where they don't get light. Is this normal (I didn't think so)? Is the lack of polyp extension taking its tole on the coral?

What kind of flow do you have? Lack of flow can cause poor polyp extension and loss of color.

Other hard/skeletal corals doing well in my tank are birdnest, stylaphora, montipora,

These are all SPS corals. What does the polyp extension look like on these? Can you take any pics?

I also add zoo and phytoplankton.

Phytoplankton is too small to feed SPS and may be causing excessive nutrient (phosphate) problems.

Would the corals prefer a 15000K over the 10000K? Do I need to reduce the amount of time my lights are on?

Corals don't care what K temp light they are under. PAR is more important than color and a 250w MH over a 29g tank is PAR overkill to say the least. 6 hrs is on the low side, but should be fine.

 

[irensing]

Thanks for the reply Capt. My water quality has been good(Ca 420-460, PH 8.1-8.3, Nitrates almost undetectable). I've tried salinty ranging from 1.022 - 1.028 over the past 6 months with no difference. Water temp is a constant 80F which is a little higher than I'd like but given my equipment and lack of funds for a chiller I'm stuck with it for now. Could this be part of the problem? I think the recent discoloration is due to slightly high PH and a phosphate spike from adding too much phytoplankton. I did a water change and used Reef Crystals for the first time before I traveled last weekend. For some reason my PH plumeted (that has never happened before) so right before I left I added some part A and it was too much. I just did a water change and fired up my phosphate reactor. My flow should be good. It is indirect but high. I can't read what model Koralia I have because it is crusted with coraline algae but it is over sized for the tank. It's about 5" L x 3.5" OD. I have it near the top of the tank in the center pointed at the bowfront so it swirls in all directions. My wetdry filter is intended for a 50g tank so the water exchange is good. I need to upgrade to a larger tank when I have the funds. This small tank is a pain to maintian especially now that it's jam packed and I have to travel for business. I will take some pics when I have a chance to show you which corals I'm having issues with.