Brown Algae (videos)

[shawnriv]

Sorry for the late response it was getting late here in Germany

Regarding UV: make sure you are using an appropriately sized pump for the UV sterilizer. If you push too much water through the UV light has not enough contact time to damage cells, if you push not enough water through you won't damage enough cells to have a meaningful effect. The instructions of the product will let you know how many gallons/liters per hour can pass through.

The alkalinity consumption is a tough question... Maybe @Dan_P has an idea.

I could imagine calcification is stalling so you don't see much alkalinity uptake anymore. Maybe some trace elements are missing as well and slowing down photosynthesis which plays a significant role in calcification and overall uptake if carbonates:

- Manganese (used for water splitting, a process of photosynthesis)
- Zinc (carbonic anhydrase enzyme to access CO2 for photosynthesis)
- Copper (electron transport / plastocyanin)
- Cobalt (vitamin B12 and substitute for Zinc in some carbonic anhydrase enzymes)
- Molybdenum (nitrate reductase for nitrogen uptake)
- Nickel (enzymes for nitrogen and carbon metabolism)
- Iron (depletes extremely fast and is required for all sorts of essential processes)

We won't know without an ICP test (preferably ICP-MS over ICP-OES) but if you aren't dosing certain trace elements daily like iron I can almost guarantee that these are slowing down certain processes. Once added back they will be consumed very fast and might even "worsen" the problem for a moment but all sorts of organisms that compete with those dinos require those elements as well.

Yes, I have the pump on the UV sterilizer set to a pretty low flow rate, to make sure it’s there is enough contact time.

As for the lack of alkalinity consumption, that’s the one I really can’t figure out. I’ve been obsessively testing Alk for the past week, and it has basically stayed between 8.4–8.5 dKH. I haven’t dosed any Alk, and it still hasn’t really moved.

I’m going to do a water change in the morning. I use AquaForest Reef Salt, so I’m hoping the fresh saltwater and trace elements might give the corals a little boost. I did get an ICP test done about two months ago and results came back with nothing out of the ordinary.

Any help from you or @Dan_P is grestly appreciated. I’m getting pretty desperate because honestly, it just doesn’t make sense to me. My Mg was 1400 when I checked today, so that seems perfectly fine. My nutrients are also in a pretty good range at roughly 9–10 ppm NO3 and 0.05–0.06 PO4.

Knock on wood, I’m not losing Acros — they just aren’t growing. They seem to be surviving, but I’m not seeing meaningful encrusting or new growth, and consequently I’m seeing essentially no measurable Alk consumption. That’s the part I can’t wrap my head around.

Here is the ICP test I did back at end of July: ATI ICP

 

[EnterName]

My Mg was 1400 when I checked today, so that seems perfectly fine.

Hobby-grade test kits for magnesium are rather imprecise, but I would not suspect magnesium to be an issue anyway.

I’m going to do a water change in the morning. I use AquaForest Reef Salt, so I’m hoping the fresh saltwater and trace elements might give the corals a little boost.

The dinos might appreciate it as well, but don't get discouraged, they won't be the only organisms that profit from the water change. Obviously water changes alone won't be enough to maintain trace element levels, but it's really difficult to decide what to dose or not to dose at this moment.

As for the lack of alkalinity consumption, that’s the one I really can’t figure out. I’ve been obsessively testing Alk for the past week, and it has basically stayed between 8.4–8.5 dKH. I haven’t dosed any Alk, and it still hasn’t really moved.

Do you tried a different test kit? Maybe your reagents went bad or so?

Here is the ICP test I did back at end of July: ATI ICP

The ATI ICP link is broken. You meant "https://lab.atiaquaristik.com/share/99f04cd4f6b698e40e3a" not "https://www.reef2reef.com/share/99f04cd4f6b698e40e3a"
It's unfortunately just an ICP-OES test so we don't know the exact levels of certain trace elements, but I would recommend dosing at least Molybdenum (Mo), Manganese (Mn), Iron (Fe), Zinc (Zn), and maybe even Copper (Cu). They are essential for various processes like photosynthesis, the nitrogen cycle, nutrient transport and uptake, etc. Water changes are not enough to maintain these elements long-term.
You can safely dose 9µg/L Mo, 1µg/L Mn, 0.5µg/L Fe, 0.5µg/L Cu, and 1.3µg/L Zn. Something like ATI daily traces #A & #B or Tropic Marin Pro-Coral A- & K+ elements can help you to maintain trace element levels long-term.

Do you happen to have a pH probe or test? Would be interesting to see if your pH is too low to allow for appropriate calcification.
Just saw your other post with pH between 7.8 and 8.2. To quote Randy:

At a pH below about 7.8, aragonite Coral skeletons and organism shells can begin to slowly dissolve, so I’d try strongly to keep pH At 7.8 or higher. In the pH 7.8 to 8.2 range, lower pH can make hard corals have to work harder to grow skeletons, but they seem to do it ok, maybe mostly because they can do it when the pH is highest during the day.

 

[xradikalx]

Glad to have found this post. I just posted yesterday with almost the exact same outbreak, based on photos. Will probably upgrade my UV sterilizer!

Thanks!