Green Star Polyp Opening now Closing?

[Chris O]

Hi All,

 

After some months of issues I finally got my tank back in decent order. I moved home from college 2 weeks ago and picked up some Green Star Polyp about 1.5 weeks ago. It opened completely about a week in, but recently only parts of it have been opening and I haven't been able to figure out why. Ph is around 8.2, 0 ammonia, 0 nitrites, and 0-5 nitrates. I understand the water here at home is different and dKh read about 6 which is low. Yesterday I started dosing to work back up but regardless the dKh has been around 6 since I've moved home so it doesn't seem to be the reason why they would suddenly not open all the way. Any ideas? I have some diatoms/dino's (don't know which) growing in the sand, is it possible its inhibiting the GSP from opening? I attached a picture of it fully opened Saturday, and then about half open today (which it has been the last few days).

 

Thanks in advance,

Chris

[Humblefish]

GSP will inexplicably close up sometimes, and then reopen fully after a week or two. Also, it may not be liking your low nitrates. Soft corals do better in tanks with elevated nutrients.

[Clown79]

If its dino's it certainly can cause corals to close up, dino's produce toxins which can kill coral and fish.

 

As for alk, have you tested newly mixed salt to see what it mixes at?

If it mixes low, that's the reason for low alk.

[roblox84]

On 4/14/2020 at 8:00 PM, Humblefish said:

GSP will inexplicably close up sometimes, and then reopen fully after a week or two. Also, it may not be liking your low nitrates. Soft corals do better in tanks with elevated nutrients.

How does one get enough nitrates for softies to be happy? Every tank I set up seemed to have a low nitrate problem and soft corals never did well. I tried feeding more, changing water less, all of which just caused more algae.

[Humblefish]

44 minutes ago, roblox84 said:

How does one get enough nitrates for softies to be happy? Every tank I set up seemed to have a low nitrate problem and soft corals never did well. I tried feeding more, changing water less, all of which just caused more algae.

What type of nutrient export system(s) are you running? A skimmer is fine, but refugiums, algae scrubbers, biopellets, etc. will typically strip the water of NO3 + PO4 that soft corals need.

[roblox84]

1 minute ago, Humblefish said:

What type of nutrient export system(s) are you running? A skimmer is fine, but refugiums, algae scrubbers, biopellets, etc. will typically strip the water of NO3 + PO4 that soft corals need.

Nothing. Only filtration I have is live rock.

[Wingy]

Look at the purple mat closely.  If you see any brown or debris lightly brush it off with a soft toothbrush.  Debris and algae can cover the mat preventing the polyps from opening.  The mat may be a bit angry after brushing but it should only pout for a day or 2.