New reefer here, having issues with Zoas!

NOLAReef · Mar 31, 2026

Hello all,

New here and dabbling into the reef hobby. I’ve done some pretty extensive research before hand and thought I was on top of everything but running into and issue with my Zoa’s.

So to start off tank is still very young, going on month 5 right now.

My current water chemistry as of yesterday:

All checked with Hanna readers.

Salinity : 1.024
Phosphate: 0.04
Nitrate : 7.3
DKh :7.3
Calcium : 450

I’ve run into non stop diotom outbreak, and up until recently my nutrients bottomed out both phos and nitrate were 0.0 so I upped feeding and they are now slowing coming back up.

Another problem I am assuming is my RO water I was an idiot and when I bought my RO unit I thought. It was a DI unit as well but it was not, only RO no resin filter, so I’m waiting on the new resin filter. As I checked my RO water and I’m at 4 TDS.

So here is my issue I have about 4 frags of various zoa’s and they all are closed and have been for over a week. Is this because of the TDS? The other chemistry seems ok for softies ?

I have a leather toadstool, and finger leather , pulsing Xenia and a mushroom, and GSP, along with 2 clowns and they are all doing fine. The zoas just won’t open up.

Any ideas I’m missing I’m all ears. Thanks!

Mr. Mojo Rising · Mar 31, 2026

4 tds is not a big deal IMO, mine has been higher at times. Remember that some people actually use tap water to grow corals, so I really doubt the 4 tds is the issue.

Its unlikely you have a 5 month diatom bloom, diatoms pass quickly unless you are adding silicates to the system somehow, but what you describe sounds more like dino's than diatoms. If you can post a picture it will help to confirm.

I would suspect they have not opened due to positioning, personally I would move it to a different spot to give it a different perspective on light and flow.

Can you share details on your light and flow?

Ultimately pictures are always very helpful for us to really understand whats happening.

NOLAReef · Mar 31, 2026

Mr. Mojo Rising said:
4 tds is not a big deal IMO, mine has been higher at times. Remember that some people actually use tap water to grow corals, so I really doubt the 4 tds is the issue.

Its unlikely you have a 5 month diatom bloom, diatoms pass quickly unless you are adding silicates to the system somehow, but what you describe sounds more like dino's than diatoms. If you can post a picture it will help to confirm.

I would suspect they have not opened due to positioning, personally I would move it to a different spot to give it a different perspective on light and flow.

Can you share details on your light and flow?

Ultimately pictures are always very helpful for us to really understand whats happening.

Thx,

I’m using AI Prime 16 on zaxby preset. Whe. They zoas were open they were not stretching for light I have them on some rock work on the low end. I’m running a reef casa 6 the standard pump and a mini nano jeabo power head.

The algae is not terrible , it’s not slimy it’s the typical brown on the sand and rock work, I see others have. the astera snails and blue leg hermits I have are eating it pretty good. I do have a tiny bit of hair algae forming but I’ve been manually removing it and been dusting off the zoas with a baster.

I’ll try and get some pics , but they don’t come out well with my phone as I don’t have a filter to reduce the UV light.

Badger_Reefer · Mar 31, 2026

Show a picture of your zoas with white light on

NOLAReef · Mar 31, 2026

Also I assumed the TDS in the water was introducing the silicates thefore why I keep getting diotoms, if it is what they are.

NOLAReef · Mar 31, 2026

Badger_Reefer said:
Show a picture of your zoas with white light on

Ok I’ll do that.

NOLAReef · Mar 31, 2026

Here some pics of the zoas.

Badger_Reefer · Mar 31, 2026

Lower your light intensity and water flow

NOLAReef · Mar 31, 2026

Overall pic of tank.

DSC reef · Mar 31, 2026

Thats low alkalinity from what I used to run, maybe your tank likes that. Not saying the TDS is the cause but the problem with showing any is that we know nothing of whats coming in through that TDS unfortunately.

NOLAReef · Mar 31, 2026

Badger_Reefer said:
Lower your light intensity and water flow

I tried that already, and I’m currently on a 40% acclimation periods for 30 days as I thought maybe the light was too much. I’ll try and lower it more.

NOLAReef · Mar 31, 2026

DSC reef said:
Thats low alkalinity from what I used to run, maybe your tank likes that. Not saying the TDS is the cause but the problem with showing any is that we know nothing of whats coming in through that TDS unfortunately.

What’s a good range for alk? 8-10?

I’m using aqua forest reef salt. And how do I slowly increase it?

DSC reef · Mar 31, 2026

I cant honestly speak for your tank but mine personally was happiest at 10dkh, I used coral pro. I wouldn't go changing salts or anything at this time, just focus on keeping your desired DKH steady. I used weekly water changes and dosed to keep my alkalinity stable but I had a lot of coral and tridacna that sucked my tank dry.