Corals are dying despite stable parameters?

ams0509 · Apr 1, 2024

Hi There!

I started my first reef tank (Biocube 32) in December 2023, and after it finished cycling in January 2024, have stocked it with two clownfish and over the next couple of months added corals in the below additions:

1) 1 Branching Hammer Coral and 2 Green Hairy (Frilly?) Mushrooms
2) 1 Pink Finger Leather Coral
3) 2 Zoas (1 Rasta, 1 AOI)
4) 1 Neon Green Pavona Coral

The hammer coral had not looked great (wasn't opening up) for a couple of months and recently died, and the 2 mushrooms are looking near-death as well. I think you can probably argue that some of the specific corals I started with were probably not the best starting corals, but I think I've generally done a good job trying to keep stable parameters in my tank. I do a 20% water change every weekend, and do a full water test the following morning. I tested my water today and had the below parameters (I use the Salifert test kits and a refractometer that I re-zero every time):

Salinity: 1.023-1.024 (Specific Gravity)
Phosphate: 0.00-0.03 PPM
PH: 8.15-8.30
Alkalinity: 8.9 DKH
Magnesium: 1110-1140 PPM
Nitrate: 0-3 PPM
Calcium: 350-360 PPM

I have also paid to have my water tested at my LFS on the same day as my testing twice and had similar/the same results. Looking back at my testing results from the past 4 months, all my parameters have consistently been within these ranges with the exception of Calcium, Magnesium, and Alkalinity, which are occasionally slightly below the recommended range. When that happens, I dose my tank with Seachem Reef Fusion 2 at the prescribed dosage. I would prefer that my corals do not continue to die, but I cannot figure out for the life of me why I haven't been able to keep healthy corals. What is everyone's thoughts? What else should I be doing?

crazyfishmom · Apr 1, 2024

Salinity is low. You need to be at 1.026 for corals to be okay. Once you get it there consistently, calcium, magnesium and alkalinity will be at the right ranges and then we can talk about nutrients. I am willing to bet that once you get your salinity up most things will start looking up though!

Cthulukelele · Apr 1, 2024

With that list of corals I REALLY wouldn't expect you to need 2 part dosing unless your pavona is the size of a salad plate. Are you sure about your salinity reading? Your mag is a bit low and you're dosing 2 part to get near NSW calcium and alk. That makes me think your salinity is low. You also should try your best to raise your phosphate and nitrate through feeding a bit more. Functionally 0 is bad for corals and especially bad for a lot of the corals you listed.

ams0509 · Apr 1, 2024

crazyfishmom said:
Salinity is low. You need to be at 1.026 for corals to be okay. Once you get it there consistently, calcium, magnesium and alkalinity will be at the right ranges and then we can talk about nutrients. I am willing to bet that once you get your salinity up most things will start looking up though!

The parameters I've been following and my LFS have been telling me to aim for 1.024 for the tank so that as the water evaporates naturally you will rise towards 1.026. Are the parameters in that link incorrect? If so, what would you say is the target range (1.026 - 1.02X)?

crazyfishmom · Apr 1, 2024

ams0509 said:
The parameters I've been following and my LFS have been telling me to aim for 1.024 for the tank so that as the water evaporates naturally you will rise towards 1.026. Are the parameters in that link incorrect? If so, what would you say is the target range (1.026 - 1.02X)?

With salinity you really want to stay in an extremely tight range. If you control nothing else, control salinity. 1.025-1.026 but really 1.026. You should be topping off your tank daily or better yet get a cheap auto top off to maintain it at exactly 1.026 always. Best thing I ever did for my tank.

Ziggy17 · Apr 1, 2024

crazyfishmom said:
Salinity is low. You need to be at 1.026 for corals to be okay. Once you get it there consistently, calcium, magnesium and alkalinity will be at the right ranges and then we can talk about nutrients. I am willing to bet that once you get your salinity up most things will start looking up though!

I keep my salinity at .025 without issues. I think low nutrients are a likely culprit. Given the margin for error, he could be close to 0/0. ICP test could give you a window as to what’s going on. ICP Test your RODI water as well and compare the two.

Cthulukelele · Apr 1, 2024

Ziggy17 said:
I keep my salinity at .025 without issues. I think low nutrients are a likely culprit. Given the margin for error, he could be close to 0/0. ICP test could give you a window as to what’s going on. ICP Test your RODI water as well and compare the two.

I more agree with Ziggy here. 1.024-1.026 are all salinities you can successfully run reef tanks. My concern is that you're below even that threshold given your numbers and dosing and that lack of nutrients is likely your biggest issue.

Goaway · Apr 1, 2024

ams0509 said:
If so, what would you say is the target range (1.026 - 1.02X)?

Because actual coral reefsxare at an average of 1.025.
Something you can actually google

crazyfishmom · Apr 1, 2024

Ziggy17 said:
I keep my salinity at .025 without issues. I think low nutrients are a likely culprit. Given the margin for error, he could be close to 0/0. ICP test could give you a window as to what’s going on. ICP Test your RODI water as well and compare the two.

Read the OP… 1.023-1.024. When it comes to salinity, those values seem like they’re pretty close but that’s a substantial differential in the amount of ions and concentration of those ions in solution. 1.025-1.026 should be the target for corals. Can they survive in lower? Maybe. They’re unlikely to do well long term.

ams0509 · Apr 1, 2024

Cthulukelele said:
With that list of corals I REALLY wouldn't expect you to need 2 part dosing unless your pavona is the size of a salad plate. Are you sure about your salinity reading? Your mag is a bit low and you're dosing 2 part to get near NSW calcium and alk. That makes me think your salinity is low. You also should try your best to raise your phosphate and nitrate through feeding a bit more. Functionally 0 is bad for corals and especially bad for a lot of the corals you listed.

I can't guarantee my readings are accurate but twice I've taken my own measurements and have had measurements taken at my LFS as well and the results are fairly consistent. My measurements on alk and calcium have been consistently low or at the low end of the range I've been following to I've been dosing like once per week. The other responder agreed on the salinity though, so maybe I'll try and slowly increase it to be consistently 1.026.

As for phosphate and nitrate, I am feeding my two clowns roughly 1/3 of a frozen mysis shrimp tablet every other day, and have started supplementing my snails/hermit crabs diet with seaweed with an algae clip. Would you recommend increasing the feeding from there?

vetteguy53081 · Apr 1, 2024

ams0509 said:
Hi There!

I started my first reef tank (Biocube 32) in December 2023, and after it finished cycling in January 2024, have stocked it with two clownfish and over the next couple of months added corals in the below additions:

1) 1 Branching Hammer Coral and 2 Green Hairy (Frilly?) Mushrooms
2) 1 Pink Finger Leather Coral
3) 2 Zoas (1 Rasta, 1 AOI)
4) 1 Neon Green Pavona Coral

The hammer coral had not looked great (wasn't opening up) for a couple of months and recently died, and the 2 mushrooms are looking near-death as well. I think you can probably argue that some of the specific corals I started with were probably not the best starting corals, but I think I've generally done a good job trying to keep stable parameters in my tank. I do a 20% water change every weekend, and do a full water test the following morning. I tested my water today and had the below parameters (I use the Salifert test kits and a refractometer that I re-zero every time):

Salinity: 1.023-1.024 (Specific Gravity)
Phosphate: 0.00-0.03 PPM
PH: 8.15-8.30
Alkalinity: 8.9 DKH
Magnesium: 1110-1140 PPM
Nitrate: 0-3 PPM
Calcium: 350-360 PPM

I have also paid to have my water tested at my LFS on the same day as my testing twice and had similar/the same results. Looking back at my testing results from the past 4 months, all my parameters have consistently been within these ranges with the exception of Calcium, Magnesium, and Alkalinity, which are occasionally slightly below the recommended range. When that happens, I dose my tank with Seachem Reef Fusion 2 at the prescribed dosage. I would prefer that my corals do not continue to die, but I cannot figure out for the life of me why I haven't been able to keep healthy corals. What is everyone's thoughts? What else should I be doing?

If this is a new/newer tank, hammer and Pavona may be too premature
Please post pics under white light intensity.
In relation, these all do best under moderate light and water flow and assure nitrate and phosphate not elevated. In addition calcium should be at least 400 for a couple of these corals. Mag best at 1300 and salinity is low and best at 1.025

Cthulukelele · Apr 1, 2024

ams0509 said:
I can't guarantee my readings are accurate but twice I've taken my own measurements and have had measurements taken at my LFS as well and the results are fairly consistent. My measurements on alk and calcium have been consistently low or at the low end of the range I've been following to I've been dosing like once per week. The other responder agreed on the salinity though, so maybe I'll try and slowly increase it to be consistently 1.026.

As for phosphate and nitrate, I am feeding my two clowns roughly 1/3 of a frozen mysis shrimp tablet every other day, and have started supplementing my snails/hermit crabs diet with seaweed with an algae clip. Would you recommend increasing the feeding from there?

Oh I'd feed significantly more than that. I'd double or maybe even triple that number

crazyfishmom · Apr 1, 2024

Cthulukelele said:
I more agree with Ziggy here. 1.024-1.026 are all salinities you can successfully run reef tanks. My concern is that you're below even that threshold given your numbers and dosing and that lack of nutrients is likely your biggest issue.

Agreed that based on numbers we are likely looking at 1.021-1.022 instead of 1.024.

ams0509 · Apr 1, 2024

Goaway said:
Because actual coral reefsxare at an average of 1.025.
Something you can actually google

I have googled it, thats why I've been aiming for 1.024 to 1.026 link the link I sent in the message. 1.023 is lower than I like but that was just after my water change from the weekend.

Devisissy · Apr 1, 2024

ams0509 said:
The parameters I've been following and my LFS have been telling me to aim for 1.024 for the tank so that as the water evaporates naturally you will rise towards 1.026. Are the parameters in that link incorrect? If so, what would you say is the target range (1.026 - 1.02X)?

No. You have salinity at 1.026 and you use an ATO or you get consistent on adding water morning, night everyday to keep it at 1.026. That might work for his massive displays where his hands are in it all day long, but not at home.

Goaway · Apr 1, 2024

ams0509 said:
I have googled it, thats why I've been aiming for 1.024 to 1.026 link the link I sent in the message. 1.023 is lower than I like but that was just after my water change from the weekend.

Thats very unstable, if your sg dropped from water change. I never had a coral that approved of lower sg. Aiptasia might be ok with it.