Does alkalinity vary throughout the day?

[Reefering1]

@Randy Holmes-Farley Do you think some acropora cannot tolerate alkalinity at 10dKH? Some of mine are really happy, but others could be better. Nutrients are detectable and high enough, but not too high.

I’m trying to rule out any culprits, and alkalinity is the last thing on my list. I always preferred to keep my alk higher. Do you think alk around 10dKH is universally safe for acros as long as it’s kept stable?

Do you think I can rule alk out as a culprit for why some of my acros aren’t doing too well? Or do I need to experiment with lower levels to find out?

10 ish is my preference, makes it easy to keep ph above 8.1. Can't say some don't like it. To me, the softies start looking less happy above 10dkh- but the sticks love it.(assuming the tank is not in turmoil with dinos/ algea smothering .75" growth tips)
Wild coral should be acclimated/ isolated in seperate system though.

 

[Reefer Matt]

I'm getting inconsistent alkalinity readings and it has me wondering if alkalinity can vary throughout the day like pH does? Or does any alkalinity drop just mean that the kalkwasser I've added has been consumed?

The alk demand in my sps tanks has gone up since I’ve been leaving the window open. I had to adjust the 2 part dosage up. However those in warmer climates don’t seem to see a difference.

https://www.reef2reef.com/threads/a...er-opening-the-windows.1113208/#post-13606188

 

[Miami Reef]

I really don’t know if high alk may be all or part of the issue.

Thanks for the response. I’m trying to remove all plausible culprits. I’m positive 8dKH won’t harm an acropora, so I’ll just keep it there to reduce variables.

It was the last thing on my list. I left it last because higher pH and alk is apparently good for stony growth. Oh well, my grow out contest finished, so I can experiment with lower levels without FOMO (fear of missing out).

 

[Reefering1]

Thanks for the response. I’m trying to remove all plausible culprits. I’m positive 8dKH won’t harm an acropora, so I’ll just keep it there to reduce variables.

It was the last thing on my list. I left it last because higher pH and alk is apparently good for stony growth. Oh well, my grow out contest finished, so I can experiment with lower levels without FOMO (fear of missing out).

Which acropora struggle?

 

[Miami Reef]

Which acropora struggle?

Goldie Bon R in particular. Some tenuis I got from Adam came pretty bleached, and they are aren’t getting back their zoox. I wasn’t sure if it was the alk that was inhibiting it.


Taking a better look, it seems like most of my guys are pretty happy. I’m gonna keep my alk higher because I like it there. I think I already solved the actual culprit and now I’m just in the waiting phase. I just wanted to eliminate all variables.

Here are two of my bleached acros. I don’t have a clue

 

[Hairyteeth]

Wow super bleached

 

[Miami Reef]

Wow super bleached

I guess that’s just the blue light tenuis vulnerability?

This is when it came. Other blue lighters also looked like this.

I took pictures on arrival just as a name and growth reference. I am not blaming the vendor. It’s my job to fix them lol

The one on top in the first picture was mine from several months ago, but it is also a blue light teni. I don’t know why these guys look so bleached.

 

[Reefering1]

Goldie Bon R in particular. Some tenuis I got from Adam came pretty bleached, and they are aren’t getting back their zoox. I wasn’t sure if it was the alk that was inhibiting it.


Taking a better look, it seems like most of my guys are pretty happy. I’m gonna keep my alk higher because I like it there. I think I already solved the actual culprit and now I’m just in the waiting phase. I just wanted to eliminate all variables.

Here are two of my bleached acros. I don’t have a clue

No algea is a good sign! Only time I've seen them fully bleached like that, but alive, was due to temperature. I know it gets hot here(fl), I like FedEx overnight because they arrive by 1030am(and don't sit in a hot ups truck all day).
I would place those in lower light/flow, make them work for light(increase zoox) and not push growth while they recover. Is there any color?
Looks like you changed lighting.. what did you go with, any noticeable changes to the system?

 

[Reefering1]

I guess that’s just the blue light tenuis vulnerability?

This is when it came. Other blue lighters also looked like this.

I took pictures on arrival just as a name and growth reference. I am not blaming the vendor. It’s my job to fix them lol

The one on top in the first picture was mine from several months ago, but it is also a blue light teni. I don’t know why these guys look so bleached.

Show it in white light. how does the flesh look?

 

[Miami Reef]

Looks like you changed lighting.. what did you go with, any noticeable changes to the system?

I’m still with T5. I recently switching to a bluer combo just in case the extra white and red bulbs made the corals more susceptible to bleaching.

The corals seem to do much better with blue light. I made this change recently.

 

[Miami Reef]

how does the flesh look?

It looks bone white with polyps. The corals is still alive for sure.

 

[blueoverbrown]

Yes it can change through out the day. That is why it’s recommended to test Alk at the same time each day. This will lead to more consistent readings. Are you adding manually, auto or trying to find your drop?

I dose Kalkwasser to my ATO

 

[Miami Reef]

I didn’t search around much, but here’s an article that looks at the issue:

https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2015.00122/full

I just absorbed that study; it seems like calcification can happen despite photosynthesis being reduced or very weak, noted by the reduction of oxygen produced when blue light at 450nm was used or by using DCMU which downright actively represses photosynthesis.

Despite the reduction of photosynthesis, the corals studied still calcified strongly. Something about 450nm light signaled pathways in the actual coral without the zooxanthellae needing to use photosynthesis.

At night, calcification seems limited by oxygen rather than light or pH.

So it seems like alk consumption will be strongest during the photoperiod if you use reef lights that are naturally prominent in the 450nm peak over the evening, especially taking into account that oxygen and pH are also highest during that time as well.

Further increasing oxygen during the day has little to no further benefit.

 

[Miami Reef]

In that study, even bleached corals calcified with strong blue light, which is funny since my bleached tenuis’ are encrusting their plugs as we speak.

 

[zheka757]

In that study, even bleached corals calcified with strong blue light, which is funny since my bleached tenuis’ are encrusting their plugs as we speak.

Was that you who posted pictures of bleached corals with PE. I have 2 frags with same problem. Just wanted to follow along. I dont have a solution for them.

 

[Miami Reef]

Was that you who posted pictures of bleached corals with PE. I have 2 frags with same problem. Just wanted to follow along. I dont have a solution for them.

Yes. That was me. They are starting to regain their zooxanthellae.

The alk is around 9.5-10 dKH. I don’t think it was the alk.

 

[zheka757]

Yes. That was me. They are starting to regain their zooxanthellae.

The alk is around 9.5-10 dKH. I don’t think it was the alk.

Got any tips on what do start with? Add/lower lights. Add/lower flow? My frag tank has 50 other frags in it, others are fine, just these 2 are bleached but still have PE. Something tells me leave it alone and they will recover

 

[Miami Reef]

Got any tips on what do start with? Add/lower lights. Add/lower flow? My frag tank has 50 other frags in it, others are fine, just these 2 are bleached but still have PE. Something tells me leave it alone and they will recover

Hmm. Did they come bleached or did something trigger it?

If most similar corals are fine, then the environment is likely fine as well.

 

[zheka757]

Hmm. Did they come bleached or did something trigger it?

If most similar corals are fine, then the environment is likely fine as well.

They got like that im my system