SPS frags bleaching at base, but only when placed higher in tank?

[benwilsonx]

Good afternoon!

Hoping for some help deciding on what thing/things to troubleshoot. I recently added a few SPS frags (most of my other corals are LPS/Softies) - a green pocillopora, birds nest, garf bonsai, and mile high latistella. They seemed to be happy for about a week on the sand bed, so I mounted them high on the rockwork. Within 24-36 hours of higher placement, however, I noticed they started looking pale at the base (and loss of lower polyps with the pocillopora and birdsnest). They still had polyp extension at the upper portion of the frags.

I moved them back to the sandbed, and this seems to have stemmed the progression for now. The garf bonsai may be gaining a little color back, and has all polpys extended.

My ideas so far:

Too much light, too quickly? PAR (measured with Seneye) was 120-140 on the sandbed where they started, and 175 - 200 where I mounted them on rock, which didn't seem like a huge jump to me.

Too much flow? Should I move my MP40s higher up, or turn them down? They're running on Lagoon mode at max 40%. Possibly relevant: I've had similar issues with LPS corals partially bleaching shortly after being moved to mid/high levels on rock, so I've kept these mostly to lower/middle areas thinking they were overdosed on light and/or flow.

Something with my chemistries? I have a couple of concerns with low nitrates and low alkalinity, but I'm not sure how this would explain the corals being happy until moved higher up.

Here are the details on my tank, with photos to follow. I started it in May 2021, with aquacultured live rock from KP Aquatics (which I assume accounts for my quick cycle). I've added a few batches of corals starting in August, and they have seemed to do well unless I place them higher than the middle of the rockwork. I only have two fish so far (added fairly late, in October... quarantine is taking a while), which may account for my low nitrates.

System
Waterbox 130.4
Caribsea Special Grade Sand (100 lbs)
KP Aqautics aquacultured live rock (100 lbs)
Inkbird Heater controller
ATO

Water/Salt
RO/DI from BRS 5 stage
Instant Ocean salt, mixed to 1.025

Flow
Varios 6 Return Pump, at level 3 of 5
Two MP40s, running at max 40% on Lagoon mode

Filtration
Two mesh filter socks in the sump
Reef Octopus Regal 150INT skimmer

Lighting
Two AI Hydra 32 LEDs

Dosing
Nothing yet, will likely start dosing 2-part soon (I never dosed anything with my last tank, so I'm still researching this).

Livestock
Midas blenny, Yellowhead Jawfish
Hermits, Astrea snails, cerith snails from Reefcleaners
Hitchhikers from live rock - long-spine urchin, a few small pencil urchins, lots of brittle stars, small pistol shrimp, etc. I've moved most of the crabs to the sump, although there are still a few small gorilla crabs I haven't caught yet.

Feeding
Frozen mysis or marine cuisine, 1/2 cube twice daily
Reef chili about twice per week

Parameters
Temp: 78 F
Salinity: 1.025 (Hanna salinity tester)
pH: 8.0-8.2 (there's a discrepancy between Seneye at 8.0, and Red Sea test kit at 8.2)
Alkalinity: 7.2 (Hanna)
Calcium: 460 (Red Sea)
Magnesium: 1560 (Red Sea)
Nitrate: 0 (Hanna High-range). When I test nitrate with Red Sea there's a very faint pink tinge, so maybe slightly above zero?
Phosphate: 0.1 (Hanna ULR)

Full tank shot:

Garf Bonsai before/after placement

Birdnest before/after:

Mile-high latistella before/after:

Thanks so much for any help!

Let me know if better photos would help, or if I left out any helpful details.

 

[T-J]

That birdsnest has either RTN or STN, depending how quickly it happened. I'd frag it.
The other do look bleached. There can be a number of reasons why they are bleaching. I really doubt it's your lighting, as I have my Bonzai in twice the lighting you have yours in and it's just fine. I do notice that it starts to pale in lower nitrates.
I suspect that in a tank that large, and with not very many fish, they are lacking nutrients.
As far as your flow, I think your running too little. I have a 120g tank with two MP40's and I run them between 60%-70% (various modes) during the day, and at 15% at night.

 

[benwilsonx]

That birdsnest has either RTN or STN, depending how quickly it happened. I'd frag it.
The other do look bleached. There can be a number of reasons why they are bleaching. I really doubt it's your lighting, as I have my Bonzai in twice the lighting you have yours in and it's just fine. I do notice that it starts to pale in lower nitrates.
I suspect that in a tank that large, and with not very many fish, they are lacking nutrients.
As far as your flow, I think your running too little. I have a 120g tank with two MP40's and I run them between 60%-70% (various modes) during the day, and at 15% at night.

Thanks for the info! I can try bumping up the flow (while recognizing that won't fix the nutrient issue). What do you think about the placement of the MP40s? Any benefit to moving them higher up? Right now they're about midway between the sandbed and rim.

I'll do some more research on the low nutrients. It'll probably be another month or two before I get more fish (on order, being quarantined prior to shipping). Would there be a benefit to feeding coral foods more frequently?

 

[Dburr1014]

I do agree with fraging the BN, and do work on your nitrates.
Can you also bump up your alk? Over a couple days I would try to get it between 8 and 9. This might help also.
If they color up again on the sandbed, I'm more inclined to think it would be a light issue coupled with the fact your Nitrate is low to zero. In that case, bump up your nitrate then put them up maybe halfway in the rock and then wait a week or two and then put them where you want them..
HTH.

 

[sculpin01]

Tissue loss of this sort is typically secondary to insufficient nitrate, insufficient phosphate, or both. In addition, in comparison to my last ICP my Hanna phosphate was testing about double what it actually was, so your phosphate may be less than 0.10.

I would add Neonitro and Neophos (10 cc and 5 cc daily) until you’re at 5/0.15 for nitrate/phosphate. This should get you into the ballpark of where corals will survive. Also, you will need to start dosing calcium, alkalinity, and magnesium soon.

 

[ScottB]

My sticks are never happy without a lot of fish load. Heavy in / heavy out. Fish produced ammonia is THE IDEAL food source for small polyp stony corals.

 

[Camaro Show Corals]

That is not bleaching that is STN, stn from the base generally means unstable alk. Are you running a dosing pump?

 

[Camaro Show Corals]

Your nutrients are not the main cause of this issue but are your reason for losing color and probably not helping the stn but because you are not dosing your alk and calcium is not as stable as it needs to be as well being a newer tank many will struggle with sps especially from dry rock.

 

[benwilsonx]

Can you also bump up your alk?

Also, you will need to start dosing calcium, alkalinity, and magnesium soon.

stn from the base generally means unstable alk. Are you running a dosing pump?

Sounds like working on my alkalinity is the place to start. No dosing yet, but I'll begin that next. Alk was relatively stable between 7.9 - 8.1 until about a month ago, but it's now dropping fairly quickly after a water change, currently 7.2. I assume this is a combination of adding corals and coral growth.

Hopefully I'll be able to start adding more fish soon to help with my low nitrates.

Thanks, all, for the guidance!

 

[Arcadiareef]

Your tank may need to mature a bit, sps have a hard time in fairly new systems, I would suggest you get an icp test done, and make corrections to chems, also watch your main 3 alk ca mag, if your having swings in alk you might run into trouble, as mentioned in thread also keep you phos, and nitrates up, do not let them 0 out, you might want to chk out reef moonshiners way of keeping corals, it’s made a world of difference for me.

Sounds like working on my alkalinity is the place to start. No dosing yet, but I'll begin that next. Alk was relatively stable between 7.9 - 8.1 until about a month ago, but it's now dropping fairly quickly after a water change, currently 7.2. I assume this is a combination of adding corals and coral growth.

Hopefully I'll be able to start adding more fish soon to help with my low nitrates.

Thanks, all, for the guidance!