Crazy kH consumption?

[Reef_Hobbyist]

Okay last thread of the day for me.

I was just checking my kH and it has been steady using 28ml a day until recently. My numbers were at 7.78 so I bumped it up slowly. A week later I was at 8.6 (last night) and today I am down to 8.00 even. So I am adding a little more kH to help the swing overnight until I can get my doser to get up to speed.

So I guess I will try 30ml per day now. My Ca dropped a tad bit from 420 to 410 so I will add 1ml extra.

Recap:

kH: 8.
Ca: 410
Mg: 1350

Has anyone experienced this much of a turn around in a week span? Its crazy that I was dosing 28ml and now that seems to be too little. My SPS are looking healthy as heck.

Amazing looking aquascape!!

So where are the fish hiding? I only see one....

 

[ReefMadScientist]

Without any dosing, when you see a 2 dKH drop in alkalinity you'd only expect about a 13 ppm drop in calcium and 1 ppm or less drop in magnesium.

For that reason you always see a drop in alk much more readily when underdosing, even when underdosing them all. You also see it rise first when overdosign them all.

ah thanks for the pointer!!!

 

[Randy Holmes-Farley Verified Community Expert]

Mag is sitting over 1500. I use esv 2 part. I've been lowering nitrates with water changes. Not stressing over calcium, have been checking more often because I have been tinkering with dosing. My main concern is stabilizing alk again. I was also dripping lime water, but for whatever reasons I can't keep my drip line dripping all of a sudden as well.

FWIW, folks doing regular water changes often find that unless they try to keep parameters matching the new salt water, that the dosing must be uneven.

Also, what the imbalance is can be deceiving.

Assume you use Red Sea Coral Pro salt and get about what they claim in it at 35 ppt:

calcium = 477 ppm and alkalinity = 12 dKH

And suppose you want to maintain your tank at NSW values of

calcium = 420 ppm and alkalinity = 7 dKH

It might SEEM like the mix is imbalanced to too much alkalinity, but that is not the case. It is actually imbalanced to too much calcium, and a tank using that mix to maintain the parameters above will necessarily need to add more alkalinity than calcium over time to offset the salt mix imbalance.

 

[ReefMadScientist]

FWIW, folks doing regular water changes often find that unless they try to keep parameters matching the new salt water, that the dosing must be uneven.

Also, what the imbalance is can be deceiving.

Assume you use Red Sea Coral Pro salt and get about what they claim in it at 35 ppt:

calcium = 477 ppm and alkalinity = 12 dKH

And suppose you want to maintain your tank at NSW values of

calcium = 420 ppm and alkalinity = 7 dKH

It might SEEM like the mix is imbalanced to too much alkalinity, but that is not the case. It is actually imbalanced to too much calcium, and a tank using that mix to maintain the parameters above will necessarily need to add more alkalinity than calcium over time to offset the salt mix imbalance.

And that explains why I am dosing more kH than Ca

 

[ReefMadScientist]

I have a feeling my daily dose should be around 60ml. I need a little more observation with my Apex but its starting to look like that is what it should be.

Well time to quote myself lol.

A little update about my tank: I went from 29ml or so and am now dosing 60ml and still fighting the decrease in Alkalinity. I am getting the curve to reduce so I near my happy-medium place.

No worries about any possible swings. I have been consistently raising 10ml the couple of days and my Alk has been sitting between 7.95-8.4. The reason I have to increase still is that my Alkalinity keeps lowering within a day or two. I am currently at 7.95 dkh.

 

[SPSREEFS]

Make sure them end of the line is not plugged...

 

[ReefMadScientist]

Make sure them end of the line is not plugged...

Ever since you mentioned this the other day I have been keeping an eye on it. I work in my den, tank is in the den, so I watch it dose every hour

 

[SPSREEFS]

Could not remember if I told you before.......it's the heat.......lol

 

[ssdawood]

Did you change your light schedule ot light intensity.

If not then you are going thru a growth spurt.

Sit back and enjoy everything is perfect and acros are growing.

 

[Kungpaoshizi]

Just remember, the higher alk you go, you're going to have to pay attention to 2 things that will happen once you get above 8 dkh, at least ime.
Above 8 you'll encounter the bacterial boom, and then the calcification boom from corals.

The coral calcification demand will NEVER outcompete the bacterial masses, so the big changes originally will always be the bacterial demand. But as you raise alk, after you get it stable at the new heightened number, you'll have a slower adjustment over the period of a couple weeks which is the corals kicking up their rates.

 

[Randy Holmes-Farley Verified Community Expert]

Just remember, the higher alk you go, you're going to have to pay attention to 2 things that will happen once you get above 8 dkh, at least ime.
Above 8 you'll encounter the bacterial boom, and then the calcification boom from corals.

The coral calcification demand will NEVER outcompete the bacterial masses, so the big changes originally will always be the bacterial demand. But as you raise alk, after you get it stable at the new heightened number, you'll have a slower adjustment over the period of a couple weeks which is the corals kicking up their rates.

You have found that bacteria respond to alkalinity?
I've not heard that before and cannot understand why it would be since they do not use it (unless you mean photosynthetic cyanobacteria, which do consume CO2 and might get it from bicarbonate).

 

[Kungpaoshizi]

Just what I observed... quick search yields something along those lines that backs it up.. (it very well could be the resistance to the ph changing that yields a higher metabolic rate, thus faster "consumption" of alk)
Though several sources indicate 'consumption of alkalinity equals this amount of ammonia dealt with'...


The Water Environment Federation’s new Operations Challenge laboratory event will determine alkalinity needs to facilitate nitrification. Operators will evaluate alkalinity and ammonia by analyzing a series of samples similar to those observed in water resource recovery facilities.

This event will give operators an understanding of how alkalinity works in the wastewater treatment process to facilitate nitrification, as well as the analytical expertise to perform the tests onsite. This provides the real-time data needed to perform calculations, since these analyses typically are performed in a laboratory that can present a delay in the data.

What is alkalinity?

The alkalinity of water is a measure of its capacity to neutralize acids. It also refers to the buffering capacity, or the capacity to resist a change in pH. For wastewater operations, alkalinity is measured and reported in terms of equivalent calcium carbonate (CaCO3). Alkalinity is commonly measured to a certain pH. For wastewater, the measurement is total alkalinity, which is measured to a pH of 4.5 SU. Even though pH and alkalinity are related, there are distinct differences between these two parameters and how they can affect your facility operations.

http://wp.cwea.org/?p=11093

Another seems to point towards something similar:
ph, Alkalinity

Nitrification rates are rapidly depressed as the pH is reduced below 7.0. pH levels of 7.5 to 8.5 are considered optimal. Typical refineries run at a pH of 8-9 with no problems. 7.14 lbs of M-alkalinity are destroyed per lb of ammonia-nitrogen oxidized.
http://www.environmentalleverage.com/Nitrification-balance.htm

Another very detailed breakdown to numerical values to satisfy nitrification demand of alk:
Alkalinity Consumed by Nitrification :
In lbs/day
(10 mgd ) x (31.5 mg/l) x (7.14) x (8.34) = 18,757 lbs alkalinity as CaCO3per day
In mg/l
(31.5 mg/l) x (7.14) = 225 mg/l alkalinity as CaCO3 consumed
FlowTKN conc.lbs. of alkalinity required per lb of ammonia-N nitrified
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCMQFjAAahUKEwiBk9OtgPfHAhVFDpIKHYpICe8&url=http://www.dec.ny.gov/docs/water_pdf/module2.pdf&usg=AFQjCNGUoMGr7qZ71rc_lHud14FXF-me8Q&sig2=7jSLr48EqYkw28F0o4pSnA

I'm sure there's more out there

 

[Randy Holmes-Farley Verified Community Expert]

No, I don't buy it. High alkalinity does not drive bacterial growth in reef tanks. Your case must have been a coincidence, since huge numbers of reefers have aquaria at 10+ dKH without bacterial blooms (myself included).

Nitrification (conversion of ammonia to nitrate) does deplete alkalinity, but it is not consuming bicarbonate or carbonate as a nutrient, and alkalinity in seawater is certainly not a limiting factor in nitrification. Nitrification just produces H+, which lowers pH and alkalinity.

In any case, nitrifying bacteria do not normally live in the water column to cause a "bloom".

 

[Kungpaoshizi]

I said 'boom' not bloom..

The first link touches on the subject in a whole, with this one statement.
During nitrification, 7.14 mg of alkalinity as CaCO3 is destroyed for every milligram of ammonium ions oxidized. Lack of carbonate alkalinity will stop nitrification. In addition, nitrification is pH-sensitive and rates of nitrification will decline significantly at pH values below 6.8. Therefore, it is important to maintain an adequate alkalinity in the aeration tank to provide pH stability and also to provide inorganic carbon for nitrifiers.

Also, given this graph:

One can state, that at a ph of 7.8, the nitrification rate, is not at maximum potential, given the other numerical equations based from wastewater treatment.
If x amount of alkalinity is needed to keep the ph at y parameters, there is a direct correlation to nitrification rate and thus, a required, necessary supply of buffer to keep the rates at their maximum values.

Unless you're dosing kalk, 2 part, or have a salt that is very high in alkalinity(even still it will happen after you stop adding fresh sw), you're going to naturally slide back down this scale after your water changes, because naturally, you're NOT dosing alkalinity thus the ph will fall a bit as the nitrification process occurs. (probably only to 7.6ish ph)

Going only from the graph without getting into the mathematics(or the temp compensation), a ph of 7.8 will give you what, 87% nitrification efficiency? Whereas a ph of 8.3 will give you max 99%?
That's at least a 10% difference in nitrification rates JUST from dosing a constant source of fresh alkalinity.

After thinking more about it, I guess you could say bloom right, it's an increase in the population of nitrifiers, might not make cloudy water but it's surely there.. Of course I'm just speaking as to when you provide the constant source of alkalinity input, not after it's established. (my first post)

Unless I'm wrong.. But thanks anyways Randy, I've never looked it this up, so +1 to more info

 

[Randy Holmes-Farley Verified Community Expert]

I don't agree with the thought that higher alkalinity boosts the nitrifying bacteria in a reef tank, but assuming it does, I can't imagine why anyone would think it any sort of concern or something folks would have to pay attention to.

 

[Kungpaoshizi]

So you're saing ph has no influence on bacterial nitrification rates? (because ph is a product of alkalinity present, correct?)

I share it because I personally wanted to know what was going on in my tank, someone else surely must care as well. There's many types of people in the world, not all learn the same way.

 

[Randy Holmes-Farley Verified Community Expert]

So you're saing ph has no influence on bacterial nitrification rates? (because ph is a product of alkalinity present, correct?)

I share it because I personally wanted to know what was going on in my tank, someone else surely must care as well. There's many types of people in the world, not all learn the same way.

The thread here is on high alkalinity and whether that is a concern. You mentioned a bacterial "boom" response to high alkalinity, which I don't believe exists.

Moving on to the effect of alkalinity on nitrification in reef tanks, I expect there is little to none in the range of alkalinity experienced since I think it is ammonia limited, but I've never seen any data. Nitrification can't really go much faster than it already is at any alkalinity or pH experienced in normal reefs because there isn't much extra ammonia available for it to happen.

With respect to pH, there is a small effect on nitrification rates in the ocean as the pH is dropped (nitrification slows). That is thought to be primarily due to the fact that the concentration of free NH3 is lowered as pH is lowered, and it is the free NH3 that is taken up by nitrifiers. Does that mean that tanks at lower pH, on average, have more total ammonia (and maybe the same free ammonia) than similar tanks at higher pH? Maybe.

Perhaps once the Mindstream becomes available, people can correlate measured ammonia and ammonium with changes in lots of different things to see if any have an effect (including pH and alkalinity, but also, things like feeding levels and adding a macroalgae refugium, etc.).

There is, of course, a contribution to pH from alkalinity, and from the CO2 level. Together they mathematically determine pH. I think it is stretching the point to then say that alkalinity impacts nitrification rates if the effect is due to pH, just as it would be stretching the point to claim that opening windows has an impact on reef nitrification rates.

 

[Kungpaoshizi]

Has anyone experienced this much of a turn around in a week span? Its crazy that I was dosing 28ml and now that seems to be too little.

The above statement is what I was responding to. I've experienced that, and I formulated a response based off of my observations. I was not aware there is an affect of ph and alkalinity that directly contributes to bacterial metabolic rates.
I too would agree it probably does come down to nutrient levels governing the metabolic rates as well, but we can't discount the interactions as a "stretch" if they exist.
Depending upon the house too, opening a window can have a great effect.

To disprove it is one thing, but it's definitely worth discussing.

Moving on to the effect of alkalinity on nitrification in reef tanks, I expect there is little to none in the range of alkalinity experienced since I think it is ammonia limited, but I've never seen any data. Nitrification can't really go much faster than it already is at any alkalinity or pH experienced in normal reefs because there isn't much extra ammonia available for it to happen.
I think your statement here has been answered though through the example links I posted. Again, I would bet you're spot on with it being 'ammonia limited' in most tanks, but every tank is different, so it's entirely possible for a reef tank to not be ammonia limited but alkalinity limited. (and you've seen some data now though wastewater treatment, that specific data nullifies the ammonia-limited side of the discussion as I'm sure they NEVER see a lack of ammonia, so they've been privileged to see the data firsthand)

But good talk, at least we have more guidelines to troubleshoot problems in our tanks with the additional information

 

[Randy Holmes-Farley Verified Community Expert]

I think your statement here has been answered though through the example links I posted. Again, I would bet you're spot on with it being 'ammonia limited' in most tanks, but every tank is different, so it's entirely possible for a reef tank to not be ammonia limited but alkalinity limited. (and you've seen some data now though wastewater treatment, that specific data nullifies the ammonia-limited side of the discussion as I'm sure they NEVER see a lack of ammonia, so they've been privileged to see the data firsthand)

Sorry, what you posted did not say anything to suggest that nitrification could ever be alkalinity limited (or even impacted) in a normal reef aquarium where alkalinity (and pH) is already pretty high and ammonia is not.

The paper (for fresh water wastewater) said that maintaining at least a pH of 7 is desirable and that to do so in fresh water, maintaining an alkalinity of at least 4.5 dKH is desirable. The examples they give talk about starting ammonia levels of 36-257 ppm.

Since those conditions are far outside the ranges recommended for reef tanks for other reasons, I think we are in the clear.

 

[Kungpaoshizi]

Sorry, what you posted did not say anything to suggest that nitrification could ever be alkalinity limited (or even impacted) in a normal reef aquarium where alkalinity (and pH) is already pretty high and ammonia is not.

The paper (for fresh water wastewater) said that maintaining at least a pH of 7 is desirable and that to do so in fresh water, maintaining an alkalinity of at least 4.5 dKH is desirable. The examples they give talk about starting ammonia levels of 36-257 ppm.

Since those conditions are far outside the ranges recommended for reef tanks for other reasons, I think we are in the clear.

'did not say anything to suggest that nitrification could ever be alkalinity limited or impacted'?
Doesn't that graph say it all?
I see a clear difference between their numbers at 7.8 ph and 8.3.
Of course the difference of fw to sw COULD mean the difference, but I imagine when talking about bacterial processes it's probably similar. Look at the redfield ratio compared to carbon dosing. It's not applicable to it, but we have all seen it to be very similar. (some even quote the redfield ratio when discussing carbon dosing)