dKH ???

[JER-Z]

<a href=showthread.php?s=&postid=13287713#post13287713 target=_blank>Originally posted</a> by MCsaxmaster
But consider: when you changed your dosing scheme, many things changed, not just the alkalinity. How do you know that the change in alkalinity had anything to do with the changes you observed, and not any of the many other parameters that happen to change at the same time?

well the only measurable differences where increased calcium and alkalinity. pH, PO4, NO3, etc remained the same. There may be other parameters that have changed, but nothing that we as hobbyists test for changed.

I understand you study marine biology etc., but it is difficult to ignore the phenomenon known as "alk burn" that has affected so many hobbyists, no?

Maybe on paper it doesnt make sense, but for some reason high alkalinity causes problems in many SPS tanks. In my tank, dkH has been the most critical chemical parameter concerning SPS health. The more stable it is, the better the color and growth is. And when it has risen too high, i got STN and "burnt" tips. When i corrected the high dkH the STN stops and the coral heals.

Like you said, there maybe some other underlying cause that occurs when the levels are elevated. But as far as i am concerned, 1 + 1 = 2 so i will be keeping a very close eye on alkalinity from now on simply because dkH is the measurable variable that I can observe that seems to have an impact on the health of my corals.

 

[MCsaxmaster]

Ok, buuuut....

There are so, so many tanks that consistently maintain significantly elevated alkalinity and have consistently great coral health and growth. Please understand, I don't mean to discount observations, but I DO mean to understand underlying mechanisms. If 1000 refers maintain elevated alkalinity and get good results while 10 seem to have problems with elevated alkalinity that disappear when alkalinity is lowered, it does not strike me as reasonable to suggest that elevated alkalinity in and of itself is problematic. There seems to be something going on, but it is our task to figure out what

 

[Amphiprion]

I don't doubt that for whatever reason, high alkalinity in bacterioplankton-style/added organic carbon systems causes some sort of localized "burning" (mainly because I have observed it, in which case it did cease after allowing the alkalinity to drop. Keep in mind this wasn't my personal tank, either). I also have no doubts that higher alkalinity does encourage higher calcification rates, etc. (that has been proven too many times to think otherwise). What gets my attention and raises a proverbial red flag is why would these new bacterial systems cause a normally favorable situation to actually become a problem (and as such, are these systems actually as beneficial as we make them out to be?). This is one of the unanswered questions that holds me back from trying something like Prodibio, etc. (other than the initial setup and maintenance costs).

Edit: Nevermind. You beat me to the point, Chris .

 

[MCsaxmaster]

Haha, no worries

That's a question I have too. A handful of folks seem to have problems with higher alkalinity in captivity (although, somewhat elevated relative to NSW seems ok, just not too much). Almost everybody trying zeovit, prodibio, etc. seems to report problems with higher alkalinity...what in the heck is going on there? Then, look at some of the Italian reefers and whatnot that dose some sugar and maintain extremely high calcium and alkalinity with great success...

So....yeah....

 

[Logzor]

Last time I checked it was between 11-13. My sps have never been happier. I do believe my test kit was running high so I would say 10-12 DKH.

I actually havent tested in over 3 months because things are doing better than ever.

I just do the pray and dose method. Usually 30-40 mls of tech A and 30-40 mls of tech B on my 55 gallon each morning.

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=13288877#post13288877 target=_blank>Originally posted</a> by Logzor
I just do the pray and dose method.

:lol:

 

[Logzor]

Seriously, its more about willing the chemicals to do things right rather than actual measuring and real chemistry.

 

[Amphiprion]

<a href=showthread.php?s=&postid=13288913#post13288913 target=_blank>Originally posted</a> by Logzor
Seriously, its more about willing the chemicals to do things right rather than actual measuring and real chemistry.

Damn, I need to tell that to my old chemistry professors. Bending chemistry to your will seems like a good start.

 

[kirstenk]

Kudo's for an excellent post!!!! I just might have to cyber stalk you.

<a href=showthread.php?s=&postid=13271457#post13271457 target=_blank>Originally posted</a> by MCsaxmaster
Consider some of the other things mother nature provides:

hurricanes/typhoons, extreme low tides leaving corals exposed and baking in the sun, crown of thorns starfish, cold snaps in winter, extreme low salinity after big rains, smothering turbidity, etc.

Natural does not imply ideal by any stretch of the imagination. Corals and other calcifying organisms certainly can and do grow well enough at NSW levels of alkalinity, but there's no reason to think that NSW alkalinity is the ideal situation. It may simply be "good enough", and indeed, that is exactly what all of the available data suggest.

And in terms of scleractinian evolution, we're looking at 230+ million years, not mere thousands. But, to be fair, there have been really significant secular changes in seawater chemistry during that period.



Why wouldn't we be able to know that? Ramp up the alkalinity and measure various parameters (e.g., calcification, linear extension, net primary production, etc.) and see what happens. Many such studies have been conducted, including work I've done for my master's. In every case the corals calcify significantly faster with higher than NSW alkalinity and generally have higher rates of net primary production. There has been no indication of any problems either in short-term or long-term studies that have been done in otherwise normal conditions.



See above: there's no reason to think that what nature provides is ideal but rather just good enough. If we don't have a good reason to deviat from nature, I agree that it's a good baseline--we know that will work at least well enough. However, when there ARE good reasons to deviate from nature (e.g., not putting crown of thorns starfish in our aquariums), why wouldn't we?

As for stability: if there is anything that is uncommon on shallow reefs and reef flats, where calcification is near a maximum, it is stability. Granted, corals are likely to see much more fluctuation in alkalinity in our aquariums than in most natural situations, but why would fluctuation in and of itself be harmfu? In nature they may see conditions vary from "sufficient" to "slightly marginal" in terms of chemistry. In captivity we may well be able to provide variation from "very good" to "sufficient"--that strikes me as perhaps a more ideal situation for growing corals.



You say this based on...?

Chris

 

[MCsaxmaster]

<a href=showthread.php?s=&postid=13291546#post13291546 target=_blank>Originally posted</a> by kirstenk
Kudo's for an excellent post!!!! I just might have to cyber stalk you.

Ha, ok? :eek2: