Coral Not Growing/ Dying Off

[Slidecf]

Hey guys, I need some help.


I'm having trouble with my corals—they're either dying (especially euphyllias) or not growing since I set up the tank. For a while, I tried dosing Aquavitro’s Fuel twice a week, but to be honest, I didn’t see any difference. I also tried feeding the corals, but there were no results either. This past month, I’ve been dealing with some algae (or cyano? Not sure).


The light turns on at 10:50 AM, ramps up to 100% at 11:00 AM, stays like that until 7:00 PM, then ramps down to 0% at 11:00 PM.
Here’s all the info you might need and some pictures.

Water Parameters:

Corals Overview:

• GSP – The first coral I added to the tank (it's been there for about 8 months). It's the only one that has actually shown some growth, but reeeeally slow, considering some people say it's like a plague.
• Zoas – Stable. Most of them haven’t grown since they were added about 4 months ago (only one died – King Midas). They’ve been closed up for the last couple of weeks.
• Torch – Died. The first euphyllia I added to the tank (8 months ago). At first, I had some trouble with euphyllia-eating flatworms but got rid of them completely. Eventually, it shrank to death.
• Hammer – Added 3 months ago. One head died, and the other is shrinking.
• Frog – Added 3 months ago. Currently shrinking.
• Goniopora – Added 8 months ago. Stable—no significant growth. It bleached for a while, but now it looks okay.
• Mushrooms – Pretty much stable. One of them appears to be growing a new head.

My Setup:

• Tank Size: 40 Gallons
• Salt: Aquaforest ReefSalt
• Light: AquaKnight V3 60W
• Skimmer: RedStarfish SQ90-Plus
• Fish: 2 Ocellaris / 1 Royal Gramma /
• 1 Coral Banded Shrimp / Some hermit crabs and turbos

Some pictures (right before i cleaned the tank):

The algae or cyano:

Frog (it used to be much bigger/open):

 

[BaileysTank]

Hi! So I might have a few ideas, what exactly are your water parameters? If your parameters are ok I would then lean towards your flow. It looks like you only have one wavemaker in a 40 gal which isn’t too much. Also do you know the par on your lighting?

Wishing you the best and I’m happy to answer questions.

 

[JonoH]

Your temp is a bit on the warmer side.
Tank looks fairly new also - how long has it been set up?

Some of those coral really need an established tank, can be very touchy to changes in thinks like Alk and Temp.

 

[Slidecf]

Hi! So I might have a few ideas, what exactly are your water parameters? If your parameters are ok I would then lean towards your flow. It looks like you only have one wavemaker in a 40 gal which isn’t too much. Also do you know the par on your lighting?

Wishing you the best and I’m happy to answer questions.

I added a photo with my water parameters up there but i can write them here anyway:

• Date: 09/02/2025 / Temp: 26,4ºC / Salinity 1026 / pH 8,2 / dKh 9,5 / Ca 420 / Mg 1320 / PO4 0,03 / Amm 0 / Nitrate 10
• Date: 25/01/2025 / Temp: 26,5ºC / Salinity 1025 / pH 8,2 / dKh 9 / Ca 410 / Mg 1350 / PO4 0,03 / Amm 0 / Nitrate 10

About the Flow:
Right now, I’m using only one 3,000 liters/hour wavemaker. Initially, I was using two, but they were moving the substrate everywhere and creating holes, so I had to stick with just one. I also tried moving the corals around to see which spots they were comfortable with, but in most areas, they seemed disturbed by too much flow—even with just one wavemaker. Maybe this one is too strong? Not sure.

About the PAR:
I dont really know since PAR meters are not much available in my country... These are the specs on the light user manual. My display size is 75cm L x 43cm W x 37cm H

 

[Slidecf]

Your temp is a bit on the warmer side.
Tank looks fairly new also - how long has it been set up?

Some of those coral really need an established tank, can be very touchy to changes in thinks like Alk and Temp.

Its been set up for about 8 or 9 months if im not mistaken.

 

[Lavey29]

Tank looks way to sterile for 8 months. Your phosphate is low. Euphyllia are difficult the first year

 

[slingfox]

Do you use RODI water?

 

[BaileysTank]

I added a photo with my water parameters up there but i can write them here anyway:

• Date: 09/02/2025 / Temp: 26,4ºC / Salinity 1026 / pH 8,2 / dKh 9,5 / Ca 420 / Mg 1320 / PO4 0,03 / Amm 0 / Nitrate 10
• Date: 25/01/2025 / Temp: 26,5ºC / Salinity 1025 / pH 8,2 / dKh 9 / Ca 410 / Mg 1350 / PO4 0,03 / Amm 0 / Nitrate 10

About the Flow:
Right now, I’m using only one 3,000 liters/hour wavemaker. Initially, I was using two, but they were moving the substrate everywhere and creating holes, so I had to stick with just one. I also tried moving the corals around to see which spots they were comfortable with, but in most areas, they seemed disturbed by too much flow—even with just one wavemaker. Maybe this one is too strong? Not sure.

About the PAR:
I dont really know since PAR meters are not much available in my country... These are the specs on the light user manual. My display size is 75cm L x 43cm W x 37cm H

Hmm, well the tank looks really new has it been running for 8 months with the lights on and everything? The rocks and substrate are really white for 8 months

 

[Sdoutreefer]

Your Po4 is pretty low… 0.03ppm isn’t great; should get it up to 0.09.

As others have said, your system looks way too clean for 8 or 9 months. Need to get that thing dirty.

 

[Slidecf]

Do you use RODI water?

Yes... RODI Water

 

[Slidecf]

Hmm, well the tank looks really new has it been running for 8 months with the lights on and everything? The rocks and substrate are really white for 8 months

Pretty much 8 months, with the lights on and the rocks. My first recorded water parameter test is from 06/24/2024. Maybe the lights make the rocks look so white? I had trouble with hair algae for a while—the rocks were completely covered with really long strings —but I eventually got rid of it. Then I had some cyano (or maybe still do). You can also see some green coloration on the rocks if you look closely at the frog picture.


Anyway, I don’t have much experience with reef tanks (this is my first one), so if you say it looks too clean, I trust you.

 

[Slidecf]

Your Po4 is pretty low… 0.03ppm isn’t great; should get it up to 0.09.

As others have said, your system looks way too clean for 8 or 9 months. Need to get that thing dirty.

Hmmm, interesting… Any tips? Should i dose PO4?

I’m feeding the fish once a day. I tried feeding twice a day for a while to see if PO₄ would rise, but I didn’t see any difference. I also tried dosing Aquavitro’s Fuel twice a week and feeding the corals once a week, but PO₄ didn’t increase either. After a while, I got worried about overfeeding and potentially causing algae issues or making the cyano problem worse.

Right now im fighting this thing that i dont really know what it is... Its getting a little bit better in the last week but it was disturbing some corals (specially zoas and the GSP)

 

[Sdoutreefer]

Hmmm, interesting… Any tips? Should i dose PO4?

I’m feeding the fish once a day. I tried feeding twice a day for a while to see if PO₄ would rise, but I didn’t see any difference. I also tried dosing Aquavitro’s Fuel twice a week and feeding the corals once a week, but PO₄ didn’t increase either. After a while, I got worried about overfeeding and potentially causing algae issues or making the cyano problem worse.

Right now im fighting this thing that i dont really know what it is... Its getting a little bit better in the last week but it was disturbing some corals (specially zoas and the GSP)

That looks like dinos, which is a result of low nutrients… I’m going through the same thing.

If over feeding does not affect your nutrients, then yes, I’d go ahead and dose.

What is your bio-load?

EDIT: 3 fish is too small of load… appears that dinos is the culprit. Get your nutrients up ASAP. 10pm for No3 is fine, but 0.03 for Po4 is too low. Try and get that up to 1.0ppm.

 

[Slidecf]

That looks like dinos, which is a result of low nutrients… I’m going through the same thing.

If over feeding does not affect your nutrients, then yes, I’d go ahead and dose.

What is your bio-load?

EDIT: 3 fish is too small of load… appears that dinos is the culprit. Get your nutrients up ASAP. 10pm for No3 is fine, but 0.03 for Po4 is too low. Try and get that up to 1.0ppm.

For a while, I had five fish… but my Firefish completely disappeared (maybe the coral banded shrimp turned it into a snack—I never found its body). I've been feeding some shrimp every once in a while to the coral banded since this happened. My Midas Blenny jumped through a reeeeally tiny gap in the tank cover—I later found its body inside the closet under the tank. Since I don’t have any jumping fish now, I removed the cover.

I will try to dose PO4 to see if things get better... thanks so much for the help!

 

[Sdoutreefer]

For a while, I had five fish… but my Firefish completely disappeared (maybe the coral banded shrimp turned it into a snack—I never found its body). I've been feeding some shrimp every once in a while to the coral banded since this happened. My Midas Blenny jumped through a reeeeally tiny gap in the tank cover—I later found its body inside the closet under the tank. Since I don’t have any jumping fish now, I removed the cover.

I will try to dose PO4 to see if things get better... thanks so much for the help!

No problem… you’ve got a bigger issue than not keeping coral alive tho. Start looking into Dinoflagellates. If you have a LFS with a microscope, see if you can take a sample of that stringy, bubbly stuff into the store and get an ID on what species of Dino you have.

Dinos are tough, and a lot of hobbyists end of tearing down their tank due to the inability to defeat them. Start doing research on them… it’s not fun.

 

[Slidecf]

No problem… you’ve got a bigger issue than not keeping coral alive tho. Start looking into Dinoflagellates. If you have a LFS with a microscope, see if you can take a sample of that stringy, bubbly stuff into the store and get an ID on what species of Dino you have.

Dinos are tough, and a lot of hobbyists end of tearing down their tank due to the inability to defeat them. Start doing research on them… it’s not fun.

Unfortunately, i guess that’s not an option… I’ll research them and do my best to get rid of them.


Also, do you have any product recommendations to raise my PO₄? I read some posts recommending Seachem Flourish.

 

[Sdoutreefer]

Unfortunately, i guess that’s not an option… I’ll research them and do my best to get rid of them.


Also, do you have any product recommendations to raise my PO₄? I read some posts recommending Seachem Flourish.

I use Neo-Phos from Brightwell Aquatics. Tropic Marin also makes a No3+Po4 addiditive that is supposed to be really good.

The Neo-Phos is great. Just make sure you go slow with it and follow the dosage instructions exactly. It’s some pretty potent stuff. Make sure you’re testing until you get a good handle on how your system reacts.

Again, your bigger issue is going to be the dinos. That stuff will out compete all beneficial bacteria. I’m about to do a 3-day blackout on my tank once I get my Po4 at a stable/acceptable level. I have some of it documented on my tank thread if you want to do a spin through it and see some of the struggles.

 

[JonoH]

My 2c for what it's worth....you may be too early for those types of coral.

Try some leathers and mushrooms to start! Maybe some Zoa's.

Euphillia Corals and Goni's are touchy and a need a more stable/advanced system.

 

[Slidecf]

I use Neo-Phos from Brightwell Aquatics. Tropic Marin also makes a No3+Po4 addiditive that is supposed to be really good.

The Neo-Phos is great. Just make sure you go slow with it and follow the dosage instructions exactly. It’s some pretty potent stuff. Make sure you’re testing until you get a good handle on how your system reacts.

Again, your bigger issue is going to be the dinos. That stuff will out compete all beneficial bacteria. I’m about to do a 3-day blackout on my tank once I get my Po4 at a stable/acceptable level. I have some of it documented on my tank thread if you want to do a spin through it and see some of the struggles.

Nice... just bought Neo-Phos. Thanks for the tip!

I was doing some research about dynos and found this post. Maybe this helps you too
https://www.reef2reef.com/threads/how-i-beat-dynos-hopefully.1031029/

 

[Sdoutreefer]

Nice... just bought Neo-Phos. Thanks for the tip!

I was doing some research about dynos and found this post. Maybe this helps you too
https://www.reef2reef.com/threads/how-i-beat-dynos-hopefully.1031029/

Can you post any more pictures of your tank? Back wall, sand, closeups of rock work?