alkalinity discussion

[Reefin' Dude]

This is from the article linked in post #81 since it is suggested in that post that we shoot for the levels recommended in that article by Randy Farley:

"I suggest that aquarists maintain alkalinity between about 2.5 and 4 meq/L (7-11 dKH, 125-200 ppm CaCO[SIZE=-1]3[/SIZE] equivalents), although higher levels are acceptable as long as they do not depress the calcium level."

I don't know why the poster chose to link it and then make a different recommendation.

Sps and some lps do not do well at all when alk drops into the 6's . 8's and 9s work well for me with very low nutrients . Growth is very good In addition to a margin of safety the higher alk can make it easier for corals to offset any high fluctuation in PO4 or other elements of alkainity other than carbonate that may occur and show up in a total alkalinity test.

now look at the levels for NSW. that is why i would recommend 7-8 instead of levels that can be nearly 75% higher than what the organism could find in the wild. these organisms have evolved to live in NSW conditions. a level of 11 is 50% higher than NSW levels. would you recommend somebody run their calcium above 700? same percentage over, if 11 is an acceptable high.

Randy's article was written in 2004, at the height of the DSB craze. this helps in pointing to something else going on with alk, than just the corals. before the DSB craze keeping alk above 9 was problematic.

i posted the article to compare the differences between what is "recommended" and what is actually found in NSW levels. if the organisms we want to keep come from the NSW environment, then why not replicate the same levels? if we run into problems, and the levels are not what those NSW levels are, then why not go back to the NSW levels as a start? we can not make any assumptions that something is wrong, without a known good base.

how is recommending levels that are not NSW not following what is found in the Randy article? NSW are obviously the best, one would need to provide references as to how and why anything other than NSW would be better. Randy even posts a caveat for upping the alk, one needs to maintain Ca. the more alk, Ca, and Mg we add the greater the chance that we are mucking around with the actual salinity of the system. luckily we do have some leeway with this, but the more we up the levels the more we change the entire composition of the water in the system and the more likely it is getting further from NSW levels. we test for S.G., not for salinity.

if nitrate levels are not 0.1ppm and phosphate levels are not 0.005ppm, how do we know if we have very low nutrients? if these are are the levels of NSW levels, would that be considered normal levels, and anything above be considered high? it seems silly to think that just because our test kits are not accurate enough to measure the NSW levels does not mean that we can think that they are low or even very low. they may be low for what we can read, but that has little to do with whether or not they are low in the environment we are actually trying to replicate.

why would there need be such a large elemental carbon source in a system unless there is a large biomass using up the vodka? what is this large biomass if it is not the heterotrophic bacteria? what would happen if the vodka were to stop? what would this biomass feed on? the articles have shown that heterotrophic bacteria will utilize both CO2 and carbonate if an easier elemental C is not available. why would this not be occurring in those systems, that do not dose an elemental carbon source? why are we even feeding all of these heterotrophic bacteria in the first place? what if the waste products they are feeding on were to be removed before the heterotrophic bacteria had a chance to feed on them?

G~

 

[tmz]

You are not making any sense. The recommended level is 7 to 11dkh and has been consistently so well beyond the date of the article. Sand beds have nothing to do with it. NSW levels for surface waters are PO4 0.005ppm and NO3 0.1 to 0.2ppm. They are higher at depth and in some more turbid areas.
You keep alluding to your system. What exactly do you keep in it with alk at 6 dkh?

Heterotrophic bacteria can not fix CO2 or bicarbonate. Hence They do not use CO2 or bicarbonate.
Chemoaurotrophic/lithotrophic bacteria like the nitrospira that oxidize nitrite mentioned in one of the articles you linked., do use CO2 and some bicarbonate in limited amounts ;preferences for one or the other are dictated by CO2 levels in the water.
The ammonia oxidizers get their energy from the nitrogen hydrogen bond and are unique in that ability.
Your position is silly ;it reminds me of a draw by numbers puzzle book with lot's of dots some of which are accurate and some not . There are no numbers to guide the connections ,resulting in a pages full of cryptic scribble.

 

[Reefin' Dude]

i did not say kept my tank with alk below 7. it has gone below 7 alk, but it is not kept there.

of course the inorganic levels are going to be higher in turbid waters. are we wanting to keep our tanks turbid?

posts 55, 59, and 68, all contain links to references that show that bacteria can uptake both CO2 and carbonate for a carbon source.

how can a tank have low alk, but not have low Ca? if we know that hermatypic organisms need to uptake alk and Ca in balance, than if the low alk is caused by the hermatypic organisms, then there is also going to be a serious drop in Ca in by the OP, correct? what is the precipitate formed above the cyano discussed in post 31, and why is it formed there? is it calcium carbonate, sodium carbonate? could this not be the balance for the loose H's?

something is not adding up. there are a lot of threads that discuss this exact same problem. low alk, but normal Ca, with alk not being able to be raised. in most cases these are new tanks or tanks with a cyano problem or do not have any hermatypic organisms.

G~

 

[blanden.adam]

posts 55, 59, and 68, all contain links to references that show that bacteria can uptake both CO2 and carbonate for a carbon source.

Hey man, honestly I'm a little bit frustrated that this conversation is still going on. I feel like you aren't even reading my replies to you. You aren't paying attention to the details of the reactions you are discussing, and you are coming up with the stone cold wrong answer.

One more time. Heterotrophs cannot fix carbon from CO2. Autotrophs can. They do this by coupling the energy requiring CO2 fixing reaction with other energy producing reactions, the most commonly known one being photosynthesis where you derive energy to drive the reaction from light (notably, cyanobacteria can do this reaction). However, when this happens with bicarbonate, the molecule must net release an OH-, which can then go on to react with a gaseous CO2 molecule to form another bicarbonate. Thus, no effect on alkalinity. This consumption has nothing to do with organic decomposition.

The reaction that does have to do with decomposition is nitrate production. Nitrate is produced in the form nitric acid, so protons are released when it is produced. This does consume alkalinity. However, when nitrate is consumed, the reverse happens and bicarbonate (or hydroxide or any of the other alkalinity equivalents) are released, paying for the alk it consumed when it was produced. Thus, no real drop in alkalinity unless the nitrate is accumulating. Not produced and absorbed, but accumulating.

Organic acids may also be released in a number of biochemical processes. However, their levels are rather low and the effect it has on alkalinity will be small, particularly compared to consumption by calcifying organisms.

I don't understand why you are clinging to this idea that the bacteria in our systems are eating bicarbonate. It's just not true.

 

[Reefin' Dude]

then where is the bicarbonate going? it can not be from the hermatypic organisms either. both Ca and alk would be low in that case, they are used up in equal amounts.

G~

 

[blanden.adam]

It's not going anywhere really. The ratio of Ca to alk is 20ppm to 2.8 dKH. Standard error on calcium test kits is typically +/- 10-20 ppm, alk test kits +/- 0.3 dKH ish, and that's with perfect technique. So, you can lose 3 dKH out of nowhere and not see it reflected in your calcium at all.

Then there are actual disequlibria that manifest themselves over time, like a slow nitrate buildup, magnesium and strontium replacement of calcium. Over weeks and months this can cause a measurable difference.

Water changes can also significantly impact the levels of calcium an alkalinity depending on how different the freshly mixed samples are from the levels in the tank and the size/frequency of the water changes.

In the case of 2-part, there's also measurement error in the making of the solutions. We typically use incredibly crude tools to measure the chemicals (i.e. measuring cups), particularly alk as it is so compressible. Furthermore, when the alk is baked you can't be completely confident of it's conversion status unless you are careful to over-bake it and use it right away as we don't store them in airtight containers under a CO2 free atmosphere.

So, in short, there are a lot of variables that can make it look like your using a lot more alk than you actually are.

 

[tmz]

i did not say kept my tank with alk below 7. it has gone below 7 alk, but it is not kept there.

You should be more careful abut that. BTW, I asked before and did not receive an answer:what type of aquairum do you keep;what corals and animals do you keep in it?

of course the inorganic levels are going to be higher in turbid waters. are we wanting to keep our tanks turbid?

Is that your new theory? Obviously you missed the point again

the articles have shown that heterotrophic bacteria will utilize both CO2 and carbonate
posts 55, 59, and 68, all contain links to references that show that bacteria can uptake both CO2 and carbonate for a carbon source.

None of those are about heterotrophic bacteria. Oops, blew it again or are just misrepresenting the point as you did with Dr. Farley's article.

how can a tank have low alk, but not have low Ca? if we know that hermatypic organisms need to uptake alk and Ca in balance, than if the low alk is caused by the hermatypic organisms, then there is also going to be a serious drop in Ca in by the OP, correct? what is the precipitate formed above the cyano discussed in post 31, and why is it formed there? is it calcium carbonate, sodium carbonate? could this not be the balance for the loose H's?

Nonsense, Adam explained it nicely 1dkh drop goes with about 7ppm calcium often undetecte. Yet another miss.

That's 5 strikes.Are we bowling?


Suffice to say there is a ton of nonsense posing as knowlege in these posts and others on other threads that need to be addressed. Folks may choose to listen to it but I've had enough and have better things to do with my time and energy. Being heterotrophic I need some carbohydrates. So, this will be my last post on it ; unless I change my mind and decide to watch a perfect game ,ie find 12 strikes in a row.

 

[bertoni]

Moved to a new thread. This discussion has nothing to do with the original question.