Why is my reef using so much potassium?

[Brandon McHenry]

Hi all!

So I’ve been wondering why my tank is using so much potassium. I dose 10mL per day of Brightwell potassium on my 40 gallon mixed reef and it seems to still decline. I started dosing potassium in April after testing my water with a Salifert Test kit and getting a reading of 300ppm. I eventually got the potassium up to 400ppm but even with 10mL per day my potassium is still reading 380ppm. This value has been verified by a Triton ICP test. Any ideas on what could be causing this? I’ve never had to dose potassium in any of my other reef tanks. Thanks!

 

[JPergamo]

I'd like to piggyback this question because my system does the same as well. One thing I have noticed is a correlation between letting my macro grow crazy and a drop in K but other than that, it still drops relatively quickly in my system even without that as a factor.

 

[Brandon McHenry]

I'd like to piggyback this question because my system does the same as well. One thing I have noticed is a correlation between letting my macro grow crazy and a drop in K but other than that, it still drops relatively quickly in my system even without that as a factor.

Interesting. I don’t have any macroalgae in my system but I do know that some types use potassium as an important trace element. I’m curious to see if others have experienced similar things or if something may be out of whack in my system.

 

[Brandon McHenry]

In case it is helpful I’ve added my Triton ICP Test from a few weeks ago for the rest of my parameters.

 

[Daniel@R2R Verified Admin]

Interesting question. Following for the answer. #reefsquad

 

[Big E]

Carbon dosing can make K drop, especially some of the commercial products.

Do you do water changes? Check the K in your fresh make up water to make sure it's near 400.

What else is in your export system?.........there may be something you use that's pulling K.

 

[Brandon McHenry]

Carbon dosing can make K drop, especially some of the commercial products.

Do you do water changes? Check the K in your fresh make up water to make sure it's near 400.

What else is in your export system?.........there may be something you use that's pulling K.

Thanks for the response! I do not currently do any carbon dosing on this tank.

Weekly 5 gallon water changes are done on my 40 gallon system with Brightwell NeoMarine salt. I did check the potassium of the mix and it came out to 400ppm as advertised.

My export is pretty basic as this is an Innovative Marine AIO tank. I have live rock and sand, a Tunze Comline DOC 9004 DC protein skimmer and my weekly water changes. I just recently added some of Brightwells Xport cubes for more biological filtration but my issue with potassium started long before that.

Hope this helps!

 

[Randy Holmes-Farley Verified Community Expert]

Hi all!

So I’ve been wondering why my tank is using so much potassium. I dose 10mL per day of Brightwell potassium on my 40 gallon mixed reef and it seems to still decline. I started dosing potassium in April after testing my water with a Salifert Test kit and getting a reading of 300ppm. I eventually got the potassium up to 400ppm but even with 10mL per day my potassium is still reading 380ppm. This value has been verified by a Triton ICP test. Any ideas on what could be causing this? I’ve never had to dose potassium in any of my other reef tanks. Thanks!

Have you measured your salt mix at the salinity you use? Maybe it is low.

In general, potassium is a balance between inputs with foods and tissue growth of organisms in the tank. So using low potassium foods, and especially dosing N and P and not potassium can cause it to drop.

 

[Randy Holmes-Farley Verified Community Expert]

Carbon dosing can make K drop, especially some of the commercial products.

Do you do water changes? Check the K in your fresh make up water to make sure it's near 400.

What else is in your export system?.........there may be something you use that's pulling K.

No method we use is specific for potassium removal. Only cell and tissue incorporation takes up significant amounts.

 

[Randy Holmes-Farley Verified Community Expert]

Interesting. I don’t have any macroalgae in my system but I do know that some types use potassium as an important trace element. I’m curious to see if others have experienced similar things or if something may be out of whack in my system.

All organisms have higher internal potassium in their cells than is present in seawater.

 

[Brandon McHenry]

Have you measured your salt mix at the salinity you use? Maybe it is low.

In general, potassium is a balance between inputs with foods and tissue growth of organisms in the tank. So using low potassium foods, and especially dosing N and P and not potassium can cause it to drop.

Yes the potassium at the salinity I mix to has tested 400ppm. I will do another test on my next batch to confirm.

As for food I feed a mix of hikari mysis, spirulina brine, omega brine, rotifers, krill and EZ pods. I also add a mix of different phytoplankton and powdered zooplankton mixes for coral as well. Despite this I have had minimal growth as of late (just my zoas) while my montipora have looked dry and grey. This is why I did the potassium test in the first place. Is 10mL per day on a 40 gallon tank more than the average?

 

[Big E]

No method we use is specific for potassium removal. Only cell and tissue incorporation takes up significant amounts.

That could be but I know Zeo users always had an issue with keeping up K. Back in the day the zeolite stones were targeted as the reason I'm not sure if that's their thoughts now.
That system uses so many bottles of additives I'm sure some of it is adding back P04 and N03.

When my K has dropped I was using Tropic Marin bacto balance and it does specifically say it's has a P04 additive to keep levels more balanced.

So I do understand your point but it is more glaring when using these products.