why aren't my corals opening up

[Spartanman22]

my parameters are as follows
nitrates: 0
nitrites: 0
Ph: 8.2
Alkalinity: 300ppm (i notice everyone posts theirs as like 9 dkh
my kit says 300 ppm is the ideal range)
Calcium: 420
salinity: 1.024

I have a 75 gallon tank with roughly 80-90lbs of lR,
20 gallon sump, skimmer, 2x250 mh and 4x60 watt pc supplements,
Inhabitants are:
Fish:
Scopas tang
Potters Angel
two yellow tail damsels
maroon clown
twin spot goby(do not know if he is still alive i havent seen him in a while)
Inverts:
few snails
about 10 large hermits
2 pocelin crabs
Corals:
pagoda cup
finger leather
pocilipora
zoos
palythoas
mushrooms
torch
plate coral
kenya tree
colt coral
finger leather
long tentacle anemone

The corals that wont open are the pagoda cup, the finger leather,
pocilipora. The first two show no since of dying just not opening up, but the pocilipora is starting to fade in its colors. One last thing is that I have a rather large amount of green algae and am in the process of setting up a phosban reactor. I will try and get pictures up if you need clarification for anything.

[Salamander]

Try checking phosphate levels and get that reactor set up.

[mouscacha]

Here's a converter for your alk
http://www.saltyzoo.com/SaltyCalcs/AlkConv.php

Regarding your reactor

#1. Put about 1/4 to 1/2 the amount it states on the bottle to start. Next time you are changing out the phos remover, add 1/4 more until you reach the max level.

#2. rinse the phos remover well (Run a water change through it)

My mistake was #1. I went full force and bleached a few frags.

[R.L.Young]

Is it just me or does that alk. seem really high at 16.8dkh

[mouscacha]

I'm kinda new to the hobby, but mine is 11dkh... It does seem high...

[R.L.Young]

11DKH Is the top end of where your alk. should be I'm not new to the hobby but I am new to actually understanding the chemistry of the tank. I've spent the last 4 weeks studying the chemistry forum, and the little sticky topics at the top off the page,was most likely be the best thing I've done for my tank in a long time.
Post your numbers in the chem forum, and see what the pros think, but i'm betting its the alk, in which case you will most likely be told to stop adding additives ,do a water change, and let it come back into range on its own.

[Spartanman22]

Ok thanks for the answer but I dont add anything to my tank and I perform weekly water changes. How am i supposed to lower my alkalinity?

[CeeGee]

what alk test are you using?

[BLKTANG]

Its possible that your angel is doing some snacking.

[cpl40475]

try moving them into a lower flow area they may be getting to much flow. As weird as that sounds

[ReefTECK]

Its possible that your angel is doing some snacking.

I think that's probably a reasonable idea to explore, there are many others to consider also.

But phosphate should be monitored for sure. Anything above .08ppm PO4 is going to stress sensitive sps corals, and prohibit calcification.

Maybe not a bad idea to do a small water change, and add a polyfilter just in case it is somehow heavy metal poisoning. Look for powerheads or pumps that have impellars that are dirty, they can chew at the inside of power heads. Unlikely but you probably don't want to gamble with the possibility.

I accidently got a small amount of zinc in my aquarium, I keep a Maglight flashlight near the tank to inspect things with regularly. I noticed that the bulb was getting dim so I slid the batteries out to see what size they were (i couldn't remember). A couple days later everything in my tank was showing inhibited polyp extension and I went through a bunch of water changes added a polyfilter and got things back on track. Several days later I went to replace the batteries and realized how corroded and leaky the batteries inside of it were. Didn't loose a darn thing luckily. Eagle Eye!

Good luck