corals not opening-help!

Not enough details. How long havet he coral been in the tank? You don't give Alkalinity, which coral can be finnicky about. Post a pic of your tank and for now stop the water changes, you are disrupting the tank.

 

With a fairly new Instant ocean hydrometer,i allways rinse it well after every use.

 

Could that also be why at almost 8 months i'm having pretty big diatom bloom?

 

it wasn't b/c of rinsing or air bubbles. the counter weight on a lot of these swing arms are slightly off. they will give a constant error. even brand new. i was getting consistent readings of 1.025. I tested my LFS water with it and got 1.014 while it was really 1.024. i think u should let a friend or LFS test your salinity.

 

diatoms come from silicates i think. I don't think salinity would cause that.

 

Alk reads about 180-200dhk on the stick?,i'm fixing dinner and typing,i'll post a pic in a short order.The last corals added was 1 1/2 months ago,nothing has been added or removed from the tank since.

 

Heres some pics of whats going on,i noticed the corals and snails before my water change everything was fine before,now it's getting worse,the diatoms are much heavier today.(sorry,my cameras not the greatest)

 

Grinder,

In the 3rd pictures I see what appear to be bubbles. Are those bubbles from the diatoms or are the bubble algae that the diatoms are covering up?

If the bubbles come with the diatoms, they aren't diatoms. You have a dinoflagellate bloom.

 

Allright now i'm getting somewhere,YES they are air bubbles coming from what i'm calling diatoms.Will that cause my coral and snail issues??

 

Yes, they can. Some species have toxins (google Red Tide). Unlike Cyanobacterias, a waterchange actually tends to feed them rather than make them go away. Additionally, different from cyanobacteria, increasing the flow actually makes them worse.

A quick search on 3Reef on dinoflagellates or snot algae will give you good cures. I'll give you the basics here though. Siphon out as much as you can, turn off your lights for several days (you're corals will be fine...trust me), and keep your pH elevated during this time too.

EDIT: The old saying is true.....A picture is worth a thousand words.