Potassium... should we be dosing it?

coralcruze · Jan 22, 2017

Hey randy,
I tested my potassium levels in my tank and it fluctuates between 390-420 between water changes.

should I be dosing potassium? if so is there a bulk product you recommend getting as alternative to store bought in a bottle?

Thanks so much!

Diesel · Jan 22, 2017

If if fluctuates between 390 and 420 you are good and no need of dosing>
If you run a ULNS the K's can deplete more than regular and sometimes water changes can't keep up with it to keep balance and than we required to dose.

coralcruze · Jan 22, 2017

thanks for the reply... what potassium supplement do you dose?

Diesel · Jan 22, 2017

I use the K from Aqua Forest, no particular reason.

JimWelsh · Jan 23, 2017

You could dose potassium chloride, or better still, a mixture of potassium chloride and potassium sulfate with a 7:1 ratio by weight.

Diesel · Jan 23, 2017

There are so many potassium products on the market but what ever you do if you can keep up the level with water changes you don't need to dose the potassium.
Btw, that count's for everything, testing before you wanna dose not just assume John and Mario are dosing so I will dose what ever and how much they are dosing.
Bad things can happen if you over dose.

Sabellafella · Jan 23, 2017

coralcruze said:
Hey randy,
I tested my potassium levels in my tank and it fluctuates between 390-420 between water changes.

should I be dosing potassium? if so is there a bulk product you recommend getting as alternative to store bought in a bottle?

Thanks so much!

Imo K is a pretty abundant element in saltwater, and to tell you the truth, thats basically the reason why i test for it. Ive seen nothing different in my tanks from dosing potassium, i stopped dosing because i would do it by hand and got lazy(at 2ml daily). Never wound up adding a dosing pump. Kept it around 380-450. What i have seen, around the time i first started using triton, K would turn up around 300. Around that time i was having problems with corals, but who knows. I think everyone should test for it though, it could be a parameter that can potentially be very important.

watchguy123 · Jan 23, 2017

If you need to dose nitrate, you can choose KNO3 whether spectracide or KNO3 granules

Diesel · Jan 23, 2017

watchguy123 said:
If you need to dose nitrate, you can choose KNO3 whether spectracide or KNO3 granules

No discussion on No3 (Nitrate)

Randy Holmes-Farley · Jan 23, 2017

coralcruze said:
Hey randy,
I tested my potassium levels in my tank and it fluctuates between 390-420 between water changes.

should I be dosing potassium? if so is there a bulk product you recommend getting as alternative to store bought in a bottle?

Thanks so much!

If that is the detected level, then no, no need to dose any. I never did and it stayed fine for 20 years.

IMO, there's no a priori reason to assume potassium depeltes, and it often does not.

jwshiver · Jan 24, 2017

I run a Zeovit system and have a hard time keeping my potassium levels up. For my system I need to dose 3ml in morning and 3ml in the evening with Zeovit Pohl's K-Balance Strong to keep it at an average of 390. This product is highly concentrated and can be easily overdosed and cause tip burn. I use the Salifert potassium test kit. Before I started dosing, my levels stayed around 350. Corals seem to have responded favorably, however there seems to be so many variables that can make corals happy or tick them off who knows if this is worth it other than piece of mind for me.

Tajaba · May 9, 2017

Hey guys! since this is the latest potassium topic I could find I figured I'd post my question here. I have a fairly new tank that has been running for about 4 months. My refugium however has been running for around 6 months. I grow seagrasses in there as well.I noticed that my K level (which was 350-360 (33ppt salinity) dropped to close to 300 in about 3 months, I don't really do any water changes (maybe 30-50l here and there on a 4000l system). My question is what happens in a low K system? would it affect my coral growth? fish spawning? I take out the old seagrass leaves every 2-3 days, is that where my K is going? I have been dosing fauna marin easy K 21ml every week for the past 4 months and still its dropping. I have been following on all of Randy's thread and I couldn't figure out where all my K is going!

Randy Holmes-Farley · May 10, 2017

The issues I've heard of in low K systems is certain sps corals begin to do poorly.

I certainly expect the seagrass takes out K, and if you are providing them N and P with effectively less K than the N

:K ratio in them, that might drive it down.

What are you feeding/dosing that contain N and P?

sundog101 · May 10, 2017

I've been keeping my K at around 420. It takes quite a bit dosing to keep it there. Would I be right to assume the corals are taking it up, or could it be something else? (I don't have sea grasses but do run an ATS.)

Coronus · May 10, 2017

I started testing and dosing K about 6 months ago maybe. First test I was low around 360. I use Brightwell Aquatics. Both my systems are sps dominated and I have to dose K every 3 weeks or so to bring it back up to 400-410. It def depletes. I do regular water changes and it does not replenish it fully. I feel it is important. The Basic 4 IMO! Cal, Alk, Mag, and K! Water changes replaces the rest.

Tajaba · May 11, 2017

Randy Holmes-Farley said:
The issues I've heard of in low K systems is certain sps corals begin to do poorly.

I certainly expect the seagrass takes out K, and if you are providing them N and P with effectively less K than the N:K ratio in them, that might drive it down.

What are you feeding/dosing that contain N and P?

Hi Randy, my P is still hovering around 0.03-0.05 ppm (with a hanna checker) and my NO3 is around 0.5ppm (slightly pink when looking from the side with a salifert) I have noticed that everytime I dose K the refugium grows a bit, then it quickly stops again, been having this happen every week. The SPS haven't grown but they are changing to a lighter color. I dose KNO3 and a modified vsv formula. I don't dose phosphate as I still have some leftover from fish food

Do you think there is a connection between the redfield ratio and K in our system?

as always, thankyou!

Randy Holmes-Farley · May 11, 2017

I do not think there is any particular import to the Redfield ratio in the water of a reef tank. Absolute numbers, yes, not the ratio between them.

There certainly is a typical uptake ratio between the various ions (N, P, K, etc.) since many organisms use them in roughly similar proportions (don't confuse that with needing them in the water at those ratios).

In your case, I can't be sure why you get a boost in the filter when dosing KNO3, but I'd think it much less likely to be the K since that is not getting changed much with each dose and more likely N or an impurity in it, such as iron.

Myka · May 11, 2017

coralcruze said:
Hey randy,
I tested my potassium levels in my tank and it fluctuates between 390-420 between water changes.

should I be dosing potassium? if so is there a bulk product you recommend getting as alternative to store bought in a bottle?

Thanks so much!

Does your potassium level change when you're standing in your tank? ;Woot Sorry, couldn't resist. I'm pretty sure you meant, "I tested the potassium level in my tank..."

I wouldn't be concerned with it fluctuating that amount. Obviously the salt mix you're using is high enough in K that it is able to replenish what your system is using. I think if you start adding K then the system will get excessive K.

Tajaba · May 11, 2017

That may indeed be the case. I still have no clue why I am rapidly depleting my K though, guess I'm gonna have to chalk it up to my seagrass for now!

Donovan Joannes · May 11, 2017

My birdnest always RTN from base up whenever K is low. I don't know how low, as testing for K using salifert kit makes my eyes and brain out-of-sync trying to figure out a "baby blue" color change. It (RTN) stopped once K is fixed.