Zoa's are not making it


Premium Member
I don't know what is going on with my zoas. I got them from another reefer. I expected them to take some time to open, which they did and they were open for about 4 days in a row. Then, they started closing. 98% of them have been closed for about 2 weeks now and several are melting away. I also lost my xenias. I have frogspawn, a hammer, GSP, and some mushrooms that all seem to be okay and doing well. I only have a small YWM and a golden head sleeper goby in the tank. I put the zoas from the top down to the bottom just to see where they would do better. I have some bubble algae that came on one of the rocks with the zoas, but it's not growing very well and there isn't really much else in the way of algae growth. I have some dragon's breath that is doing fairly well in the display. This is a long post, but I was trying to give as much information as possible to help you guys help me.

My tank is a biocube 32g LED. I have the stock lights. I was running the lights on too short of a cycle, but now I have them running as follows:
LC1 1pm-9pm all whites
LC2 12:30pm- 9pm blue/white/full spectrum
LC3 8am-1am- blue moonlight strip

my parameters are
salinity- spot on 1.026
Nitrites- 0
Nitrates- 10ppm
dKH- 9
Phos- 0-.25 ( hard to tell with API test kit, will upgrade to hanna at some point)
Mag- 1560 ( just tested today, realize its a little high especially with calcium being lower)
Cal- 420
PH- 8.2 ( been pretty steady, but was at 8.0 and I used some buffer to get it up a bit last week. I did it slowly over 3 days)

Protein skimmer
Intank Media basket in middle chamber with-
Filter Pad
Chemipure Blue
and then I have some live rock in the other side of the middle chamber next to the InTank media basket

I have been dosing with Part A and B from Kent ( branded as Coralife) and using Coralife Buffer to manage KH and PH. I used some baking soda in water to get the initial PH back to par. Other than that, just RODI and Tropic Marin Pro Reef salt mix.

I know I'm probably being to meticulous and overthinking things, but the only thing that seems to be out of whack is the magnesium and thus the calcium is lower than it needs to be. The only inverts I have are 2 hermits and two nassarius snails. I put some Trochus in initially, but they passed in about 2 days. I have a few limpets and things that were hitchhikers on some rocks and then some sponges and small feather dusters throughout the live rock. There is a little bit of dioatoms that comes and goes on the sand, but this is my third tank and I was in the hobby for 8 years before I got out for about 5 and then got to this tank. The stuff I went through was so minimal and have had going on by way of algae and diatoms has been insignificant than what I've experienced in the past. I just can't figure out for the life of me why my zoas aren't thriving and happy. I also was pretty bummed about the xenias, but I know xenias can be finicky and it was a 50/50 shot when I put them in regardless of my tank. I'm just dissapointed in the zoa situation because I really want to get some zoa gardens in my tank.

The brighter picture is from June 1, so that picture is 10 days ago. The zoas were closed then. The dark pictures ( tried to do this before the lights turned off, sorry its dark. I can get brighter pictures tomorrow if needed. But it shows the same thing, and there isn't much change in the corals from June 1 through today. The only thing that is different is I moved the one frag of zoas down to try to see if that might help and it seems like it's doing about the same. I don't know much about pests and stuff, but I've watched a bunch of videos to try to decide what to do next, just figured I should ask here first.

Any help would be appreciated.


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Premium Member
Staff member
so, you don't mention how long the tank has been set up. but its very clean. possibly too clean.
for the few small hard corals (frogspawn, and hammer), you can probably make do with just water changes until they get much larger.
you might try leaving it be for a few weeks - dont dose, or chase any PH. let it find a stable level. clean the class, top off, and feed the fish.
let the nitrates rise to 20 or so before doing a (smallish 8-10g) water change.
also - you don't mention temperature. zoas in particular tend to close up if too cold - IMHO they like it warm (78-82f), but other corals may not (particularly up in the 80's) - and almost none of them like quick swings (more than 2 deg a day)- which can happen easier in a smaller tank like yours.


Premium Member
My temp stays around 80 degrees. I have the thermostat set to 79, but it usually runs warm so the heater rarely kicks on. At night, it stays between 78-79 without the heater, but with the heater set at 79 it stays there. During the day, it heats up to 80. I've seen it get to 81 before, but rarely. Its very stable as far as temps go. The lack of phosphates, or too low, could be the issue and then the magnesium is a little high at 1560 with the calcium at 420. I haven't been dosing daily, just every other day or two and only about 80% of what the bottles say. The reason I started that is because the PH was at 8.0 and I was just trying to get it up a little. Now it's 8.2. I stopped trying to raise it because I didn't want to mess anything up.

Tank age- I've had it running for about 2 months. I got it from a reefer who had it running for 2 years. He just took his fish and the corals out and left it running until I got it. It's the same sand and the same rock, then I added some dry rock from a previous tank I had. Other than that, it's the same it's been for 2 years prior to me bringing it home. It wasn't ever dry, the sand still had the same water in it. I just let it run empty for 2 weeks with new water and added aquavitro seed to help level the bacteria filtration.


Premium Member
Staff member
well, that seems fine for temp. and, tank should be cycled at least - may still mature a bit (diatom issue should go away in 6-8 months).
Ma/Ca really aren't a problem for zoas. so water parameters are good. (although again, a bit clean for zoas to thrive - but they should open)
so, that leaves two things - toxins and flow. it's not impossible that something got in the water that is an irritant (soap, etc). purigen should help there, but you might try a big water change or two, and then run some old fashioned activated carbon for a week or two to be sure.
for flow - i see two powerheads and good surface agitation - definitely enough - but could be too much (just make sure the output isn't hitting them directly).
lastly, i have had some success with dips when zoas close up and refuse to open. if its not the the water or the flow etc irritating them, it could be bacteria. i use sechem reef dip or iodine, dip for about 2 minutes and gently clean them off, then rinse and return to the tank. hard call because this does irritate them, which will make the issue worse if the dip doesn't remove the cause for ongoing irritation. might be worth tying on a few, and see if they get better than the non dipped ones after 2-3 days.


Premium Member
I dipped with revive and then did hydrogen peroxide yesterday, just to see if that would help. The zoas look worse after 24 hours. From what I saw, it's a good solution for zoas specifically, so I thought I'd try it. I did see some critters that came off, but I don't know what they were other than a couple of very small flat worms and a few pods. I have one zoa frag that was white when I put it in, it had some green algae on it so I scrubbed the frag clean after the dips. It's still closed today, but the polyps still have orange color and look like they might make it if the open again.

I definitely think it was too much flow at first. These pumps are 2100gpm at max out of 20 speeds, I have them on 2 which is very low. There is a quite a bit more flow coming from the return pump. Both are set on speed 2 of 20, 20 being the highest setting. I had them on 10 which is 50% and the euphyullias were struggling. I turned everything down and the euphyllias opened up and are happy now. They are also set to random flow so they ramp up and down randomly. One is about 2 inches from the top and towards the front, not aiming at anything. The other is behind the live rock and down about 6 inches from the top of the water. It might still be too much, I'm not sure.

The frogspawn is opened today as are all the mushrooms. The hammer still isn't fully opened, but the heads aren't fully retracted either. So it might be a flow issue. I know the goby has been sifting and sand was on the mushrooms next to the hammer, so it might just be his drama. The GSP doesn't look like it made it through the dips though, looks rough and the polyps are not opened at all. I guess I killed that just dipping it. I tried the hydrogen peroxide and maybe that was a bad decision for that one.

I appreciate the suggestions.