Struggling with (some) acros

[KK's Reef]

I have bought acro frags from various vendors over the last year. The only acros that thrive are of the rainbow tenuis variety. The other species that tend to STN are non-tenuis. My tank is over a year old and here are the params that I test/am conscious of.

Salinity: 1.025 - 1.026
Temp: 78- 81
Alk: 7.7 - 8.3
PO4: 0.01 - 0.05

I dose AFR so the few times that I tested calcium and mag the numbers were in line. I also do a 40% water change once a week, and my salt mixes at the same alk within my normal range, so there's no danger of alk swings with water changes. The only other thing I dose is AB+ and live phyto every other day, and a capful of Microbacter7 with wather changes. Tank inhabitants are a small clown and a small firefish, a hermit, a few snails, 3 sexy shrimp, a sand conch, and a nassarius snail. I don't see any pests on the acros themselves. Again, the tenuis in the tank are growing and thriving.

I have a few theories of why I lost some frags.
1) Experienced a heatwave and found tank temp to be 84 degrees when I got home. I now keep a fan over the tank and it kicks in when the temp hits 81.
2) Maybe the frags I bought have not been in captivity that long, and probably stressed too much during shipping.
3) I didn't acclimate them (I know, this is a subjective topic).

The one non-tenuis acro that I bought has been with a particular vendor a long while, and that one survived the longest even without acclimation.

I love my rainbow tenuis, but I love the other species as well, and looking for tips from the community to help me increase the survivability.

 

[blaxsun]

You may want to post some images so some of the resident SPS experts can weigh-in.

 

[RedReefer]

Low nutrients? Tank size?

 

[KK's Reef]

Low nutrients? Tank size?

4 gallon pico. PO4 is almost always above 0.00 and never over 0.10. I also does phyto and aminos.

 

[vetteguy53081]

Alk is low which in turn will likely be affecting your CA and in turn PH
What kit are you using to check alk and what salt mix are you using?
Also assure you dont have elevated water temp and salinity

 

[Dburr1014]

I disagree with the previous post, alk is spot on for what you posted in nutrients. If you want higher, you would need more nutrients.
You posted a 3 degree temp. It's that the swing? You need to nail that down better. That can be an issue.

I have bought acro frags from various vendors over the last year. The only acros that thrive are of the rainbow tenuis variety. The other species that tend to STN are non-tenuis. My tank is over a year old and here are the params that I test/am conscious of.

Salinity: 1.025 - 1.026
Temp: 78- 81
Alk: 7.7 - 8.3
PO4: 0.01 - 0.05

I dose AFR so the few times that I tested calcium and mag the numbers were in line. I also do a 40% water change once a week, and my salt mixes at the same alk within my normal range, so there's no danger of alk swings with water changes. The only other thing I dose is AB+ and live phyto every other day, and a capful of Microbacter7 with wather changes. Tank inhabitants are a small clown and a small firefish, a hermit, a few snails, 3 sexy shrimp, a sand conch, and a nassarius snail. I don't see any pests on the acros themselves. Again, the tenuis in the tank are growing and thriving.

I have a few theories of why I lost some frags.
1) Experienced a heatwave and found tank temp to be 84 degrees when I got home. I now keep a fan over the tank and it kicks in when the temp hits 81.
2) Maybe the frags I bought have not been in captivity that long, and probably stressed too much during shipping.
3) I didn't acclimate them (I know, this is a subjective topic).

The one non-tenuis acro that I bought has been with a particular vendor a long while, and that one survived the longest even without acclimation.

I love my rainbow tenuis, but I love the other species as well, and looking for tips from the community to help me increase the survivability.

 

[sculpin01]

84.5 F is considered the bleaching threshold for many open ocean corals (inshore corals tend to be more thermally resistant). So you probably stressed your corals with that. For such a small water volume, you would probably benefit from a temperature controller (Apex or otherwise) that switches between heater and fan to keep your tank stable.

Here's an example from one of my tanks (also set to a diurnal/nocturnal 1.2 degree variance):

 

[KK's Reef]

Alk is low which in turn will likely be affecting your CA and in turn PH
What kit are you using to check alk and what salt mix are you using?
Also assure you dont have elevated water temp and salinity

I don't think my alk is low. Low to me would be in the 6's.

I use Hannah for alk testing.

Salinity is nailed down. Temp is nailed down for the most part, other than the couple of days of a heatwave that I let the temp go north of 83.

 

[KK's Reef]

I disagree with the previous post, alk is spot on for what you posted in nutrients. If you want higher, you would need more nutrients.
You posted a 3 degree temp. It's that the swing? You need to nail that down better. That can be an issue.

I feel like the temp is the culprit too. Two straight days of where the tank likely went over 83 degrees. I usually have a fan over the tank when I know it's going to be hot. But I'm in Bay Area and weather changes here more than Lady Gaga changes outfits.

 

[KK's Reef]

84.5 F is considered the bleaching threshold for many open ocean corals (inshore corals tend to be more thermally resistant). So you probably stressed your corals with that. For such a small water volume, you would probably benefit from a temperature controller (Apex or otherwise) that switches between heater and fan to keep your tank stable.

Here's an example from one of my tanks (also set to a diurnal/nocturnal 1.2 degree variance):

Good info.

I have an Inkbird to control the heater and fan. The fan usually isn't always on the tank, but I think it's going to have to be, specially during the summer.

 

[vetteguy53081]

I don't think my alk is low. Low to me would be in the 6's.

I use Hannah for alk testing.

Salinity is nailed down. Temp is nailed down for the most part, other than the couple of days of a heatwave that I let the temp go north of 83.

Any drastic change in salinity or consistently low alkalinity levels will be the source of SPS issues. You have a range in alk and from what you describe an inconsistency lacking consistency. Its not that 7.7 is dangerous but you are swinging in and out of a scale that should be 8-9.5 in many cases. The concern is not the alk level but when alk is on the low end, it affects growth and produces burnt tips , ph swings and and can alter calcium levels.
Calcium and alkalinity need to be in balancefor SPS to thrive and build skeleton.

 

[DHill6]

I don't think my alk is low. Low to me would be in the 6's.

I use Hannah for alk testing.

Salinity is nailed down. Temp is nailed down for the most part, other than the couple of days of a heatwave that I let the temp go north of 83.

I don’t think your alk is low. Mine runs 7-7.5, my ph is 8.1-8.4 At one point it was 6.8 and still fine.

 

[KK's Reef]

Any drastic change in salinity or consistently low alkalinity levels will be the source of SPS issues. You have a range in alk and from what you describe an inconsistency lacking consistency. Its not that 7.7 is dangerous but you are swinging in and out of a scale that should be 8-9.5 in many cases. The concern is not the alk level but when alk is on the low end, it affects growth and produces burnt tips , ph swings and and can alter calcium levels.
Calcium and alkalinity need to be in balancefor SPS to thrive and build skeleton.

I thought it's generally believed that an alk range of no more than 1.0 difference should be fine. Mine doesn't change more than 0.5. Meaning, if I my alk is 8.2 after a water change, and after a week of AFR dosing, the alk test number before the water change is 7.7 (at it's lowest). It's usually 7.9, 8.0, or 8.1.

I hear you about the burnt tips, but I've not experienced that at all on any of the acros.

 

[Dburr1014]

I thought it's generally believed that an alk range of no more than 1.0 difference should be fine. Mine doesn't change more than 0.5. Meaning, if I my alk is 8.2 after a water change, and after a week of AFR dosing, the alk test number before the water change is 7.7 (at it's lowest). It's usually 7.9, 8.0, or 8.1.

I hear you about the burnt tips, but I've not experienced that at all on any of the acros.

You are correct about alk. It is fine.
Vetteguy is wrong about burnt tips. High alk and low nutrients burn tips. He just has it backwards.
Alk is not the source. My reef ran in the mid six range for a few months and no problems.

 

[CHIEF_OF_THE_REEF]

How old is your test kit solution? Hannah's alk I have found has less then a year before it goes bad. I would get a good manual test kit and make sure what numbers you have are accurate. I have been burned in the past with the fancy checkers so now manual tests are done every Sunday to confirm the fancy checkers I use regularly.

 

[Yellowsound]

Here’s another thought: with such a small volume, there are likely going to be significant chemistry swings if you’re doing a 40% water change 1x/week, even if you’re matching alk and salinity. Could you do smaller changes more frequently?

 

[KK's Reef]

How old is your test kit solution? Hannah's alk I have found has less then a year before it goes bad. I would get a good manual test kit and make sure what numbers you have are accurate. I have been burned in the past with the fancy checkers so now manual tests are done every Sunday to confirm the fancy checkers I use regularly.

My Hannak alk checker is about a year old.

I'm confident that it's accurate. My Red Sea salt mix mixes at approximately 8.5 dkh and I test the freshly mixed water every now and then with the Hanna and it's spot on.

 

[KK's Reef]

Here’s another thought: with such a small volume, there are likely going to be significant chemistry swings if you’re doing a 40% water change 1x/week, even if you’re matching alk and salinity. Could you do smaller changes more frequently?

Thought about that too. But I feel like as long as my dkh and calcium numbers are pretty close between the tank water and the fresh saltwater, it should be fine. If anything, I'm getting more trace elements replenished with the bigger water change volume.

 

[KK's Reef]

Well, guys and gals, I think I may have found the culprit. Due to everyone's input and suggestions, I decided to go over everything.

The one thing that I didn't do/hadn't done, was calibrate my salinity checker. Rookie move. I calibrated it this morning and my salinity is at 39.8. This whole time, I thought I was at 35.0 - 35.2.

That and the two days of high temps is what probably shocked/killed the acros.

 

[vetteguy53081]

You are correct about alk. It is fine.
Vetteguy is wrong about burnt tips. High alk and low nutrients burn tips. He just has it backwards.
Alk is not the source. My reef ran in the mid six range for a few months and no problems.

Often an alk spike can cause burnt tips which then get covered with algae or when CA gets above 450 and nutrients are low or undetectible especially nitrates which are too low, while alkalinity is higher than about 7 dKH . The nutrient level in the water is the driving factor at what level alk can be kept at safely with acro. Low alk = low nutrients and High alk = High nutrients.

@Randy Holmes-Farley - Can you elaborate ?