trace elements?

[Salty1962]

No, if anything they should be reduced. The salt mix should not contain NO3 or PO4 except maybe in very trace amounts.

Quality Salt Mixes should NOT have any N03 or P04 in it...

 

[Randy Holmes-Farley]

FWIW, salt mixes do often have a little ammonia in them, which can end up as nitrate.

 

[Randy Holmes-Farley]

How much and how long of an interval do you perform water changes? At your tank size if you do 50% once a week that should give you enough trace elements along with 2 parts dosing. Along with that aminos once or twice a week with boardcast feeding should be able to give you good colors.

I changed 1% daily, automatically and very slowly. Such changes won't supply much of something that is being rapidly depleted, such as iron, but it will constantly tug everything back toward levels in the salt mix, whether it is accumulating or depleting.

 

[Randy Holmes-Farley]

Recently, Potassium was at 300ppm and of course other minor elements were low as well. As I don´t believe I can replace every single trace element or even test for it, I always do a couple of big water changes and then I increase my dosing of trace elements. So far, during the past few years this method has worked for me and I think it is just the normal process of a higher demand of elements as sps corals keep on growing and get more demanding.

What foods were you feeding and were you rinsing them?

Potassium is a balance between food inputs and organism uptake, and there is no inherent reason that it should get depleted, so when people observe significant depletion, I try to see if there is any sort of rational reason to help explain it.

 

[JMacedo]

What foods were you feeding and were you rinsing them?

Potassium is a balance between food inputs and organism uptake, and there is no inherent reason that it should get depleted, so when people observe significant depletion, I try to see if there is any sort of rational reason to help explain it.

The blended food I make hasn´t changed much since I started making it some 25 years ago, basically salmon, shrimp, nori, clams, artemia and something I see in the market or LFS, like shrimp eggs and so. I rinse the foods before starting to use the blender, no rinsing before feeding.

As I was forced to restart the tank due to a chiller failure, I don´t have a higher bioload than before as the fish are basically the same and the sps are frags of my old colonies.

The major change I have made was the purchase of a new skimmer as the old one looked more like a rock than a skimmer and it was rated for only 600litres while the new one is rated for 3000litres.

I still dose Nopox 20ml/day like in the past two years and use UV to "fry" some bacteria to help me export some nutrients and probably... some potassium as well as I was getting over 1gl/day of very wet skimmate (I remember reading somewhere that bacteria can take some Potassium, don´t know if in one of your excellent articles or not as I read a lot about the hobby).

Also to cope with the amount of biofilm created by Nopox I started using more flocculants what made improve the skimmer´s performance and resulted in the cleaning of all the rocks and lowering of PO4. Since the depletion I have adjusted the skimmer, reducing very much the amount of skimmate and to my surprise there is so far no increase in NO3 levels.

In the two previous years my calcium reactor and 10% weekly water changes were enough to keep all the corals growing at fast rate and with good colours but now things are different. Now I am doing 20% weekly wc and trying to adjust the dosing of trace elements, so far with very good results but still in a testing/observation phase prior to be written down on the weekly schedule.

Tested Potassium using a Fauna Marin and a Salifert test kit and both were about 300ppm what in my book is way too low and made me scratch my head has the tank was rebuilt just six months ago.

Now I have been raising levels and Potassium is at the 410 mark and colours are coming back to what I was expecting.

 

[DamianOZ]

Potassium is a balance between food inputs and organism uptake, and there is no inherent reason that it should get depleted, so when people observe significant depletion, I try to see if there is any sort of rational reason to help explain it.

My tank depletes K at an average rate of 5.7ppm per day. I don't have an explanation, there are many theories, one which may be consistent for me is the use of needle wheel skimmers

 

[Randy Holmes-Farley]

My tank depletes K at an average rate of 5.7ppm per day. I don't have an explanation, there are many theories, one which may be consistent for me is the use of needle wheel skimmers

I've heard people make that correlation/claim, but it isn't really an explanation at the level I am hoping for. FWIW, potassium itself is not skimmable from seawater.

It may be true that skimming can remove whole organisms such as bacteria or phytoplankton, and hence the potassium inside of them, but even so, for potassium to drop implies that those organisms have more potassium per unit of N and P in their bodies than do the organisms used to make the foods that originally supplied that N and P (unless you dose inorganic N or P or both). That may be the ultimate explanation, but I'm not yet totally sold on it.

Generally, potassium is loose in the cytoplasm of cells. Any breakage of the cell membranes can allow the potassium to be released, but not necessarily the N and P which can be part of large structures (DNA, proteins, cell membranes, etc.) that do not wash away. That is the basis of my hypothesis that frozen foods (or dried foods) may have broken cell membranes and may then release their potassium to the extracellular fluid, and any rinsing by you or the manufacturer before adding to the tank may result in loss of potassium relative to N and P.

 

[Randy Holmes-Farley]

My tank depletes K at an average rate of 5.7ppm per day. I don't have an explanation, there are many theories, one which may be consistent for me is the use of needle wheel skimmers

That's certainly bigger than normal water changes might account for, but I think for some people, water changes with a mix slightly lower than the tank (due to low K in mix or less than 35 ppt salinity) may be a factor in K depletion. It could account for maybe 4 ppm each 10% water change.

 

[DamianOZ]

The suggestion of skimming depleting K was tossed around as a common factor with tanks running ULNS a few years ago. I respect your advice, unfortunately I don't have the knowledge to contribute a theory. May be sharing details of my experiences can help.

I have only been testing K for a few years.
System 1, 500L net, full zeovit ULNS system. used 10ml of 100,000ppm K solution per day.
System 2, same as above, using carbon dosing, used the same volume of K
System 3, current system, uses the same volume of K, yet water volume is only 170L net

Al 3 systems are very different in methodology, and to some extent, water parameters, all used the same skimmer, dosing of 3 part + K. the first two passed many many additives, chemical and organic

My current tank has no media, no GFO, no Flocculants, no binders, no carbon dosing, completely bare. I dose Alk, Ca, Mg and K solutions to maintain 6.5 - 7 dKh Alk. 395 - 410ppm Ca. 1300ppm Mg. 400ppm K
I feed some reef pearls, some nori and 1 cube of frozen unrinsed brine or mysis (Ocean Nutrition) daily. Nothing else is added other than RODI and NSW (for past 4 months, I do experiment from time to time.)
My nutrients levels are generally undetectable. I use UV but K depletion has been the same when turned off. The display is bare bottom, very minimal rock and lots of SPS.

I have observed reductions and loss of colour in some SPS, not many, when K has been lower than 360ppm which have regained colour quickly with K correction.
I have witnessed tip burn on 3 colonies when dosing K too quickly. More likely due to localised concentrations than a change in level, as I have since raised K by 20ppm over 12 hours with very gradual dosing with out issue, (ableit only the one occasion).

A question in my mind, if K levels influence pigmentation, is it though consumption, a reactive response or a transport mechanism?
Or were my observations on several occasions coincidental (possible).
Assuming Salifert K test is actually testing K, K clearly depletes and I believe my calculations are accurate, in which case, it has to be going some where.

May be I could test some skimmate for K, and test some NSW water used to defrost frozen food for changes in K.

 

[DamianOZ]

pictures give better illustration than words

 

[Randy Holmes-Farley]

The suggestion of skimming depleting K was tossed around as a common factor with tanks running ULNS a few years ago. I respect your advice, unfortunately I don't have the knowledge to contribute a theory. May be sharing details of my experiences can help.

I have only been testing K for a few years.
System 1, 500L net, full zeovit ULNS system. used 10ml of 100,000ppm K solution per day.
System 2, same as above, using carbon dosing, used the same volume of K
System 3, current system, uses the same volume of K, yet water volume is only 170L net

Al 3 systems are very different in methodology, and to some extent, water parameters, all used the same skimmer, dosing of 3 part + K. the first two passed many many additives, chemical and organic

My current tank has no media, no GFO, no Flocculants, no binders, no carbon dosing, completely bare. I dose Alk, Ca, Mg and K solutions to maintain 6.5 - 7 dKh Alk. 395 - 410ppm Ca. 1300ppm Mg. 400ppm K
I feed some reef pearls, some nori and 1 cube of frozen unrinsed brine or mysis (Ocean Nutrition) daily. Nothing else is added other than RODI and NSW (for past 4 months, I do experiment from time to time.)
My nutrients levels are generally undetectable. I use UV but K depletion has been the same when turned off. The display is bare bottom, very minimal rock and lots of SPS.

I have observed reductions and loss of colour in some SPS, not many, when K has been lower than 360ppm which have regained colour quickly with K correction.
I have witnessed tip burn on 3 colonies when dosing K too quickly. More likely due to localised concentrations than a change in level, as I have since raised K by 20ppm over 12 hours with very gradual dosing with out issue, (ableit only the one occasion).

A question in my mind, if K levels influence pigmentation, is it though consumption, a reactive response or a transport mechanism?
Or were my observations on several occasions coincidental (possible).
Assuming Salifert K test is actually testing K, K clearly depletes and I believe my calculations are accurate, in which case, it has to be going some where.

May be I could test some skimmate for K, and test some NSW water used to defrost frozen food for changes in K.

Thanks.

What 3 part are you using?

That can also be a way that K is depleted if it does not contain enough K. The reason is that the salinity rises, and when you correct back to normal salinity, K is pushed down along with everything else.

 

[DamianOZ]

That's certainly bigger than normal water changes might account for, but I think for some people, water changes with a mix slightly lower than the tank (due to low K in mix or less than 35 ppt salinity) may be a factor in K depletion. It could account for maybe 4 ppm each 10% water change.

I use NSW, which gives Salifert a reading of 390ppm
I change on average, 25% volume weekly, however this will have next to nil net change on K

Thanks.

What 3 part are you using?

That can also be a way that K is depleted if it does not contain enough K. The reason is that the salinity rises, and when you correct back to normal salinity, K is pushed down along with everything else.

My solutions are based on your DIY 2 part article.

390g NaHCO3 + H2O to make 5L (Alk ~47k5 ppm or 2660dKH) - daily dose = 216ml - consumption = ~60ppm/day
500g CaCl2 + H2O to make 3.8L (Ca ~37k ppm) - daily dose = 108ml - consumption = ~23.5ppm/day
1.9kg MgCl2 + H2O to make 5L (Mg ~47k ppm) - daily dose = 28ml - consumption ~7.7ppm/day
K (Ultimate Aquacare brand) (K ~100,000 ppm) - daily dose 10ml - consumption = ~5.88ppm/day (reduced this week to 9.7ml/d = 5.7ppm)

The system uses automatic evaporation replacement with RODI water, I monitor conductivity via Apex Controller. I don't really see any significant increase in conductivity over time, however I do periodically do large water changes.

may be you can help me with the chemistry here?
I tried but could be a fair way off
The shift in salinity is about + 0.004% per day, K is shifting - 0.014% per day

 

[Randy Holmes-Farley]

Someone who doses the equivalent of 4 dKH (71 ppm calcium carbonate equivalents) of alkalinity per day using a two part with no potassium will, over the course of a year, drop potassium quite a lot. Assuming you readjust salinity every day, it drops from 400 ppm to 237 ppm, or 0.45 ppm per day.

 

[DamianOZ]

The tank is using 5.7ppm K daily, there has to be another reason
The previous tank, 3x the volume, 3dKH per day, using the same molecular volume of K, seems a strange co-incidence.
The current tank has been using the same volume of K for 6 months, Alk dosing has increased from 80ml to 216ml, yet K remains the same.

Something doesn't add up, the skimmer is a constant, the K volume is a constant, I can't think of any other constant variable.
I adjusted my skimmer to skim quite wet yesterday, in anticipation of testing. I have just now tested, using Salifert K test kit..

Test 1 skimmate = 430ppm
Test 2 tank water = 400ppm
Test 3 skimmate = 430ppm
As the tank water tested as predicted, I didn't repeat.

 

[Randy Holmes-Farley]

I wouldn't have much confidence in skimmate testing as it may not count K inside of cells.

Have you tested the water you use for water changes?

What size is your tank?

 

[larangcon]

The problem might be as simple as turning off your skimmer for a day or so until you get your NO3 and PO4 to the level that you think will satisfy your SPS back to its normal colors. Just my 2 cents bro, I believe in simplicity with stability, and do not have my skimmer on 24/7 just 8 hours a day on a timer.

 

[DamianOZ]

tank is 4x2x1 The total water volume is 170L

I collect my own natural sea water, test results have been 390ppm or 400ppm, not sure how many tests I have done.

 

[Randy Holmes-Farley]

Perhaps you just have some organisms with unusually high internal levels of potassium.

 

[DamianOZ]

may be..

I keep mainly Acropora sp.
some zoanthis, some fish, some turbo snails. not much else