Kalk reactor = broken

I don't recommend worrying that much about pH in most cases. A pH meter is nice to have, but only when you need it....otherwise it can be like a goose chase.

All things considered pH doesn't have that great an impact if all else (nutrients, chemistry, etc) is in good shape. So worry about that stuff instead. :)
I agree with not chasing numbers, but they have shown that calcification is easier at higher pHs. Right?
 
But nobody's calcification stops at "low pH" though.....and lots of people screw up their tanks chasing pH. ;)

It's really the coral's internal pH that dictates the reaction anyway....calcification isn't even the biggest problem with low pH. (Will see if I can scare up a link on this.....I looked earlier and I'm not sure I put it on my blog yet...)
 
Proteins in the coral are responsible for secreting the aragonite...remembered that detail....still looking for the article. Grr – thought I'd posted it!!
 
Lol, you're a beast mcarroll!!!

Maybe my word choice was poor. I'll have to find what I was reading...maybe free available alkalinity would've been a better phrase. I'm at work, but looking forward to reading the article. Enzymes catalyze happiness in my life.
 
I use a 5g bucket with a BRS 50ml/min timer that runs every hour with vinegar saturated kalk in a stand next to the tank. I am a huge fan of carbon dosing to boost the microbial food chain (not for nutrient reduction although it does accomplish this) and I am also a big believer of keeping pH up if at all possible. Not chasing it, but keeping it high if at all possible. I had posted some research to low pH and bleaching and calcification years ago - but there is plenty of research with ocean acidification out there. If global CO2 is rising enough to impact reefs via lower pH (400ppm+ globally now, was under 300ppm early 1900s) then my tank has the potential to be impacted especially in summer with AC on when many homes run well over 1000ppm co2.

If it's not easy for someone to keep pH above 8 it's alright, not worth loosing sleep on or anything. But if it's not too hard to keep pH up I don't see why one wouldn't.

So kalk I get balanced ca/alk, pH boost, and carbon additions. I have it run independent of my ato and I still run 2 part.

Just my .02
 
I am a huge fan of carbon dosing to boost the microbial food chain

Certainly the danger is with letting your nutrients bomb out, but the positive effects of carbon dosing are pretty much overstated and the downsides have been completely glossed over.

Effects of organic carbon, organic nitrogen, inorganic nutrients, and iron additions on the growth of phytoplankton and bacteria during a brown tide bloom

In short, the effect on the microbial community is not a positive one, generally speaking. It's sort of a house of cards – as long as the nutrients keep flowing in you're set. The moment starvation kicks in, your massive bacterial population totally strips the tank of N and/or P. This is usually a terminal event for large parts of the microbial food web.

Carbon dosing is very much (like every other technology) a double-edged sword.

Careful how you carry it or you're likely to cut your bits off!! :D

(So many tanks full of harmful algae blooms like dinoflagellates....pretty much 100% due to this overall strategy.)

I had posted some research to low pH and bleaching and calcification years ago

Check out that link I put on post #25

Fresh research – June of this year. :)

Summary: Corals are MUCH more awesome than you or I suspected. (I get this effect about every third day from reading.....corals are so amazing. :P)

It seems like corals probably have nothing to fear from CO2. The aragonite process is not abiotic and is not dependent on the pH of the bulk seawater around it.

I also wonder if oceanic warming isn't the real issue....somewhere in the article they mentioned that corals radiated during at era where CO2 was elevated. Given that, it doesn't seem like CO2 should be the issue. Given this latest research, it doesn't seem like CO2 really could be the issue.

Now a pH spike (up or down) could be an issue for various reasons....but can a pH spike happen from atmospheric CO2? Are there pH spikes in the ocean? We know they are to be avoided in a tank. :)
 
Perhaps it's because I have been a microbiologist for so many years so I am biased, but I think perhaps you are overstating the dangers of carbon dosing. I feel the community benefit is huge, not only can many coral directly uptake acetate (or their zoox) but there are many reports of increased filter feeder populations that I have also personally experienced such as tube worms and sponges. Water chemistry and nutrient levels are important to keep monitored with every tank and dosed tanks are no exception - however do keep in mind that for the filter feeder and microbial food chain benefits are use far less carbon that one would for lowering nutrients.


The research has an important line. "Such a mechanism suggests that stony corals may be able to sustain calcification even under lower pH conditions that do not favor the inorganic precipitation of aragonite."

1st off the conclusion is "may be able to sustain".

We know corals can sustain calcification under lower pH as many people run low pH in this hobby. However it does not mean calcification in not impacted. Also calcification may not be the only issue related to pH, there is also bleaching that can be linked with heat as well.

http://www.pnas.org/content/105/45/17442.short

I had another article that showed greatly increased bleaching with lower ph 7.8 range, but I can't find it right now of course.

As I said many homes run 3x the current global CO2 amount. I see little reason to try and increase pH if at all possible.
 
hopefully this isn't too off-topic.....I still like my kalk reactor! (there!)

Water chemistry and nutrient levels are important to keep monitored with every tank and dosed tanks are no exception - however do keep in mind that for the filter feeder and microbial food chain benefits are use far less carbon that one would for lowering nutrients.

Very true and important to say! :)

This is not a "carbon is evil" discussion, folks. :) Every shred of algae and coral in our tanks is constantly dosing carbon into it and encouraging very specific bacterial communities.

So we're only figuring out our impact to the carbon cycle and how we might be obstructing or interfering with it and maybe how it stays balanced on its own. We're not demonizing anything except doomed tanks. :D I've gone long periods dosing my own tank with vinegar, but only into the reservoir for my kalk reactor to boost its output. Carbon is neither evil nor useless. :)

However, the effects of carbon dosing are poorly understood in the hobby. Witness the mystery side-effects and number of folks who use it vs phosphates.*

Regardless, the side-effects for us appear to be just as those described in the article I linked earlier for wild ecosystems with elevated carbon levels:
  • Healthy = non-elevated C levels = a slant toward phytoplankton
  • Unhealthy = elevated C levels = a slant toward bacteria
.....so we know at least some of the effects of "high carbon" when we see it. Usually only when it's too late and the dominant green algae have already died off and been replaced.

The end result is often a tank dominated by bad (literally harmful...not merely ugly) algae – not a tank with no algae. (Those only happen in pictures!)

Dino outbreaks are probably the "most popular" negative end result in the hobby, but not likely the only one as I also suspect a role for elevated carbon in "burnt tips". Need more cases to look at in detail in order to rule out (e.g.) GFO and nutrient starvation, but there seem to be no cases of burt tips that are associated with a tanks that allow "natural" carbon levels and "natural" P and N levels.

If so many folks weren't starving their tanks from Day 1 out of fear of algae, we wouldn't have near the numbers of "carbon problem tanks" that we do today. Old school methods were (are!) better in this scenario.

Fear of algae drives a lot of negative behaviors.
No nutrient spike (or crash) = No bloom = No worry​

Easy to put in an equation, but it means (in a nutshell) going slow so. I think that's the core of why it remains unpopular as a strategy.

-Matt

* To complicate matters, we have no way to assess carbon levels in our tanks the way they do in journal articles, so I can't say what "elevated" means to us with any precision. I think alkalinity is our only clue, but it's not clear if or how alkalinity, or alkalinity usage, is impacted by organic C dosing. (I think I've seen it argued that one doesn't impact the other, but I have trouble accepting this in a system that has producers of carbonic anhydrase converting back and forth.....there is a carbon cycle and this is a part of how it works.)
 

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