Kalkwasser an np pellets - not a good relationship

[williet]

Hey guys
I have gone the np pellet route and bid farewell to my dsb. Recently I had a lack of alkalinity as there was no evaporation and thus no kalkwasser being dosed. This was met with a shocking discovery - my phospates went from 0 to 2.5. This is obviously from the precipitated phosphates leaching back into my system!!! I also could not understand until now why my np pellets weren't working. This was due to have np pellets work the bacteria need a bit of p04 to aspirate for the nitrate consumption to work!!! Will be monitoring things in the week to come!!!!

Your take on this?


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[Jamie@Vertex]

An interesting observation! This has been observed in zeolith-type systems, and is due to the tanks chemistry changing. Unfortunately, the full process is not really understood. In a closed system we really see these small chemical reactions as they have no way of being diluted. Phosphate-binding has long been considered a possible issue with kalkwater as the carbonate is very chemically active in its concentrated state. A reason to reconsider Ca reactors or a type of buffering/diluting system for the kalkwater.

Your pellets should start to drop the nutrient levels, but it will take time, depending on how much nutrient is bound. Older tanks often need up to 1 year! Typically, the PO4 will stabilize at about 0.08 for a while, which is tolerable.

A couple of things to check; accuracy of PO4 test kit? If your kit is not accurate below 0.05, then it is not good enough! Balance of Ca+, Mg+ Alk and pH.

Jamie

[dallasg]

while i understand the issue, how did the po4 precipitate back? the po4 that is bound by the kalk is normally skimmed out, does your kalk not enter in the same chamber as your skimmer?

the interesting part is which is "absorbing" the po4 the quickiest, kalk the chemical way or pellets the biological way

[Quintus]

bump

[Jamie@Vertex]

Originally Posted by dallasg

while i understand the issue, how did the po4 precipitate back? the po4 that is bound by the kalk is normally skimmed out, does your kalk not enter in the same chamber as your skimmer?

the interesting part is which is "absorbing" the po4 the quickiest, kalk the chemical way or pellets the biological way

Dallas,

the calcium phosphate will not be skimmed out, rather it settles into the tank (most of it, anyway). A change in the general chemistry of the water can bring it back into solution, although this is often considered impossible. It may hang together with pH or other ionic changes in the water. Or a bacteria that sets it free. This is till an open question. The reaction with carbonate is much quicker than any bacterial action.

Any phosphorous taken up by bacteria will be skimmed out, of course. Nitrogen is, also, taken up in this process.

I will admit, I've never been comfortable with the total explanation of what does possibly happen, as it is literally impossible for us to know for sure. Small changes in water chemistry can favour specific reactions, possibly for a very short time, but enough to make a difference.

Now, let's consider what may be happening in relation to a carbon dosing system, such as bio-pellets. As this changes the water chemistry locally, in the area of the pellets, as well as generally influencing the general available ions/nutrients in the water, we will find various reactions taking place. Bacteria needs carbon, nitrogen and phosphate to build itself, plus O2. This means there will be a slight tendency to O2 depletion, which is typically compensated by the skimmer. Still, we are increasing the population of takers for nutrients. If it is possible, they will breakdown other substances to continue their reproduction/life, such as bound nutrients. Now, there is what we call the redfield ratio, which states that for every atom of phosphorous, we need 16 atoms of nitrogen and about 116 atoms of carbon. We see quickly that there will tend to be a surplus of P (PO4) due to this ratio, which means it is available for precipitation and, should there be a compatable ion, it will react. If this reaction is too strong, we see a rise in NO3, as it cannot find enough P- to be used by the bacteria. This is rare, but can happen and may be related to kalkwater. As the chemical reaction take place much faster than bacterial assimilation, the cheimcals will always be ahead, if the condition are in their favour.

I'm explaining this so that one sees how little we really understand about the complexity and that a lot is intelligent guess work. Also, this underlines the need to aim for a stabile aquarium envirnoment. Don't keep messing around for the sake of messing around. Changes need to be made thoughtfully and slowly.

OK, enough soapboxing.

Jamie

[dallasg]

@Jamie@Vertex
thanks for the detailed reply, i love learning more....

the biology of reef-keeping is a never ending blackhole

[Jamie@Vertex]

Originally Posted by dallasg

@Jamie@Vertex
thanks for the detailed reply, i love learning more....

the biology of reef-keeping is a never ending blackhole

You're telling me! The more I learn, the stupider I feel.

On the other hand, the answer to all questions is 42!
(Hitchiker's Guide to the Galaxy)

Jamie

[dallasg]

42 it is...
me too, but i love to experiement

[williet]

Ok @Dallas

To have kalk drip in the same chamber as a pump is not generally a good idea. The abrasive nature of kalk will reduce the life of your impellor IMHO.

To answer your other question. Depending on the level of phospates,it may precipitate into solid flakes which lie at the bottom of your sump and slowly leech back phosphates into your tank. ( I did not clean them out ! Lesson learnt and mistake not to be made again!!!!)

Personally I am using a kalkstirrer and the one thing I have a problem with it is that you never have a constant KH and PH. I will be now resorting to a two part dosing system.

@Adee I know you use a stirrer/reactor, how do you deal with this or is your Alk demand high enough to counter this ?


Seems like people like this thread

[Jamie@Vertex]

Originally Posted by williet

Ok @Dallas

To have kalk drip in the same chamber as a pump is not generally a good idea. The abrasive nature of kalk will reduce the life of your impellor IMHO.

To answer your other question. Depending on the level of phospates,it may precipitate into solid flakes which lie at the bottom of your sump and slowly leech back phosphates into your tank. ( I did not clean them out ! Lesson learnt and mistake not to be made again!!!!)

Personally I am using a kalkstirrer and the one thing I have a problem with it is that you never have a constant KH and PH. I will be now resorting to a two part dosing system.

@Adee I know you use a stirrer/reactor, how do you deal with this or is your Alk demand high enough to counter this ?


Seems like people like this thread

I think this is a subject we will continue to revisit. The finer our systems are, the more important such factors become in the big picture.

We are getting better, though.

Jamie

[dallasg]

my kalk reactor, reef octo KR140, is on my ATU and on a timer, i only let the kalk stir at the eve when lights are out, and i run a carx

[williet]

Originally Posted by Jamie@Vertex

Dallas,

the calcium phosphate will not be skimmed out, rather it settles into the tank (most of it, anyway). A change in the general chemistry of the water can bring it back into solution, although this is often considered impossible. It may hang together with pH or other ionic changes in the water. Or a bacteria that sets it free. This is till an open question. The reaction with carbonate is much quicker than any bacterial action.

Now, let's consider what may be happening in relation to a carbon dosing system, such as bio-pellets. As this changes the water chemistry locally, in the area of the pellets, as well as generally influencing the general available ions/nutrients in the water, we will find various reactions taking place. Bacteria needs carbon, nitrogen and phosphate to build itself, plus O2. This means there will be a slight tendency to O2 depletion, which is typically compensated by the skimmer. Still, we are increasing the population of takers for nutrients. If it is possible, they will breakdown other substances to continue their reproduction/life, such as bound nutrients. Now, there is what we call the redfield ratio, which states that for every atom of phosphorous, we need 16 atoms of nitrogen and about 116 atoms of carbon. We see quickly that there will tend to be a surplus of P (PO4) due to this ratio, which means it is available for precipitation and, should there be a compatable ion, it will react. If this reaction is too strong, we see a rise in NO3, as it cannot find enough P- to be used by the bacteria. This is rare, but can happen and may be related to kalkwater. As the chemical reaction take place much faster than bacterial assimilation, the cheimcals will always be ahead, if the condition are in their favour.

Hi Jamie

I cannot agree more with you ! I have personally experienced this issue and N/P pellets have become quite a big interest to me. I have been doing a lot of reading and also believe that the bacteria used also consume other trace elements from what I have seen - almost like what Potasium is to Zeolith setups. The Trace element I so far suspect is strontium and possibly Iodine - but that will require further research and monitoring. I believe it is an awesome technology and requires alot of trial and error and trying different things. I have been to meets where a lot of guys complain about it bleaching softies. Hence my theory on Iodine.

But none the less a very exciting field.!!!!!

[williet]

Originally Posted by dallasg

my kalk reactor, reef octo KR140, is on my ATU and on a timer, i only let the kalk stir at the eve when lights are out, and i run a carx

Do you use NP Pellets ?

[Achilles]

np pellets and high alkalinity also causes issues with corals if you running any carbon dosing you want to keep kh low like 7-9 max

[Jamie@Vertex]

Originally Posted by Achilles

np pellets and high alkalinity also causes issues with corals if you running any carbon dosing you want to keep kh low like 7-9 max

True, but you really shouldn't have your alk above 8 dKH in any case. There is no evidence of corals growing better under a higher alk and we do know that it can be deliterious. NSW levels all the way, for me.

[williet]

Originally Posted by Jamie@Vertex

True, but you really shouldn't have your alk above 8 dKH in any case. There is no evidence of corals growing better under a higher alk and we do know that it can be deliterious. NSW levels all the way, for me.

I know !!! I have a Dkh of 11 and well.... RTN city is the destination of some of my corals !

Busy dropping it slowly...

[Adee]

I've run a kalkstirrer for many years, i tend to top off (when I remember) every 4 days or so with about 8 large table spoons of kalk. i also run a CR-300 calcium reactor....i've last week added my dosing unit as well, i mix my own calcium chloride and bicarbonate of soda (for alk). I'll test tonight again to see if its enough to keep up with tanks demands.

The one perk of having a large system (volume 2500L)...is that i really need to dose a lot to overdose, though the flip side is if my system is short....i will always need to play catch up, up until last week I did this by adding kalk (slurry, 2 tablespoons of kalk morning/night) straight into the DT overflow that feeds the 2 skimmers, I have a shortlived PH spike....but normalises after 5 minutes. I'm hoping the addition of the balling method to supplement the kalk stirrer and the carx unit will allow me to cease with the kalk slurry additions.

I agree...keeping alk at 7dKH....works hundreds for me.

[williet]

Originally Posted by Adee

I've run a kalkstirrer for many years, i tend to top off (when I remember) every 4 days or so with about 8 large table spoons of kalk. i also run a CR-300 calcium reactor....i've last week added my dosing unit as well, i mix my own calcium chloride and bicarbonate of soda (for alk). I'll test tonight again to see if its enough to keep up with tanks demands.

The one perk of having a large system (volume 2500L)...is that i really need to dose a lot to overdose, though the flip side is if my system is short....i will always need to play catch up, up until last week I did this by adding kalk (slurry, 2 tablespoons of kalk morning/night) straight into the DT overflow that feeds the 2 skimmers, I have a shortlived PH spike....but normalises after 5 minutes. I'm hoping the addition of the balling method to supplement the kalk stirrer and the carx unit will allow me to cease with the kalk slurry additions.

I agree...keeping alk at 7dKH....works hundreds for me.

7dkh - I wish! I put a couple of spoons in and I get an alk of 11.3. I have now decided to go the dosing route aswell. With NP pellets it is burning my corals.