How long does it take to corals to open?

[mosareef003]

So, recently i had an issue with the ph in my tank dropping from 8.2 to 7.4 overnight. I suspect it was too much co2 in the tank since its winter in washington and i keep all the windows closed most of the day. Anyway, that seemed to stress out all my corals and they were all fully closed. its been a week and a half since that happened and most of the corals are doing good now exept my hammer and torch corals. They barely open throughout the day and fully close at night. Im asking this question because im worried they got permanent damage and theyll never fully open again. I miss their long polyps flowing with the water.

MY TANK

20 gallon cube
salinity 1.25
Alkalinity 8.5
Calcium 445
Magnesium 1300
Ph is stable at 8.2 with fluctuations 0.2 (8.0) at night

 

[Mr. Mojo Rising]

Pictures would help. Did you do a water change? I find a water change often helps with depressed corals.

 

[Tahoe61]

How long have you had the corals, and what lighting are you using?
What testing method are you using for specific gravity?

 

[mosareef003]

Pictures would help. Did you do a water change? I find a water change often helps with depressed corals.

This is how theyve been opening the past week and a half. I did do a 5 gallon water change 3 days ago.

 

[mosareef003]

How long have you had the corals, and what lighting are you using?
What testing method are you using for specific gravity?

ive had the corals for 5 months now and the lighting i dont remember the brand of the lights but ive had no issue with lighting. I use salifert testing kits for all my parameters.

 

[SliceGolfer]

Things that pop into mind:
Nitrate or Phosphate level too low
Airborne contaminant like spray cleaner or air freshener
Shrimp or crab snacking on polyps
Pest like flatworms

 

[nuvo626]

Agree it can be low nutrients they tend to like higher nitrate and phosphate

 

[Mr. Mojo Rising]

Can you take a pic in white lights? The rocks look perfectly white, which is impossible in a 5 month old tank. I'm wondering if the light is sufficient, there should be some algae.

 

[Reefer Brent]

What fish do you have?