New to this hobby, I have new zoanthids that were fully open for like 3 days. For the past 2 days they only open up a tiny bit.

[Justfebreezeit]

.8 or .08?

 

[SoFloReefer55]

.8 or .08?

Sorry, 0.09

 

[Justfebreezeit]

.09 is likely not the issue then. Rowaphos could bring you to zero, so use it with care. Its a good tool but if you are under .1 i wouldn't.

 

[crazyfishmom]

Phosphate at 0.09 is totally normal. Salinity at 1.027 is not super far off but again zoas are interesting in that regard. Hopefully that does it. Let us know how they do over the next few days.

 

[SoFloReefer55]

Phosphate at 0.09 is totally normal. Salinity at 1.027 is not super far off but again zoas are interesting in that regard. Hopefully that does it. Let us know how they do over the next few days.

update. My zoas have shown some life today which was relieving. They've been slightly open for most of the day. I'm hoping that within the next few days they get back to thriving. Also slightly off topic question. I'm gonna be away for 4 days in about 3 weeks. Should I consider getting an auto top off to make sure everything is fine those 4 days? Or just top it off all the way before leaving for the 4 days?

 

[Formulator]

update. My zoas have shown some life today which was relieving. They've been slightly open for most of the day. I'm hoping that within the next few days they get back to thriving. Also slightly off topic question. I'm gonna be away for 4 days in about 3 weeks. Should I consider getting an auto top off to make sure everything is fine those 4 days? Or just top it off all the way before leaving for the 4 days?

How big is your tank? I would recommend an ATO for anyone keeping corals just because of the added stability at relatively low cost if you can DIY and don’t get too fancy with it. If your tank is on the small side, 4 days is probably cutting it close to some major stress on your fish and corals. In a pinch you could cheat a little by doing a few small water changes over a few days before you leave to lower your salinity down to about 1.023-1.024. Then while you are gone it slowly creeps up to your target 1.026 or perhaps a bit higher. Variation in the range 1.023-1.028 is probably fine for a short time as long as it isn’t sudden. I’m spitballing this idea and never heard of it being done, but it makes sense in my mind and I have had unintentional salinity swings in this range without major issues

 

[crazyfishmom]

update. My zoas have shown some life today which was relieving. They've been slightly open for most of the day. I'm hoping that within the next few days they get back to thriving. Also slightly off topic question. I'm gonna be away for 4 days in about 3 weeks. Should I consider getting an auto top off to make sure everything is fine those 4 days? Or just top it off all the way before leaving for the 4 days?

I would not risk it. You’ve already been experiencing some issues with coral stress and salinity can be a source of that. An ATO is a life saver and you can get simple cheap ones on Amazon for less than $100.

 

[Mr. Mojo Rising]

And an auto feeder if you have fish.