Potassium Discussion

Bearjohnson

Well-Known Member
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RS Ambassador
I've been reading a lot lately on the importance of Potassium in the reef tank so I figured I'd grab a Salifert test kit (easiest to test potassium with) and a bottle of Brightwell Aquatics Potassium with my next fix of a shipment.

OK shipment came today:) and here is what I've found out so far.

My Potassium level was at 280. From what I've read 390-410 is the optimum range.

I'm not exactly sure what to expect by keeping the levels in check other than a healthier reef but I have been struggling a little with some of my SPS lately and maybe this is just one piece of the puzzle I'm missing.

Does anyone have any more information on who, what , where and why Potassium is so important and does anyone test for it in their tank?
 

yorkieUK

Member
PREMIUM
I've been reading a lot lately on the importance of Potassium in the reef tank so I figured I'd grab a Salifert test kit (easiest to test potassium with) and a bottle of Brightwell Aquatics Potassium with my next fix of a shipment.

OK shipment came today:) and here is what I've found out so far.

My Potassium level was at 280. From what I've read 390-410 is the optimum range.

I'm not exactly sure what to expect by keeping the levels in check other than a healthier reef but I have been struggling a little with some of my SPS lately and maybe this is just one piece of the puzzle I'm missing.

Does anyone have any more information on who, what , where and why Potassium is so important and does anyone test for it in their tank?


Found this elsewhere. Don't know if it helps?

Introduction
Potassium should be maintained around 400ppm. Potassium is important element in the reef aquarium but is only consumed in small amounts and is normally maintained by regular water changes. However increasingly people are finding it to be deficient in their aquariums especially when using ULNS systems.
Increasing your Potassium level in your tank is fairly easy and can be done by using an "off the shelf" liquid additive. For small tanks/adjustments this can be effective, however for the larger tanks/adjustments then it is more cost effective to add Potassium Chloride.
If your Potassium levels are high, then test a fresh salt mix to see what the Potassium levels are, if unusually high then consider changing your salt brand. Carrying out regular water changes with a salt containing less Potassium than your tank level, will gradually bring the Potassium levels down.
Application
Using the calculator below find out the dosage amount. Weigh the dosage carefully.​
Mix the dose with .5 to 1 litre of RO water. Stir thoroughly to dissolve the salts until the mixture is clear. Then drip the mixture slowly over the course of several hours into a high flow area of the tank such as weir, sump return area etc.​
Due to the sensitivity of marine organisms, it is not advisable to raise potassium by more than 10 ppm per day.​
When increasing potassium, it is not advisable to perform other supplements at the same time.

Excess potassium levels can lead to algae blooms, so do not overdose.​
If you are unsure about anything discussed above, raise a thread in the 'Help and advise' or 'Chemistry' areas of the forum.

 

Wrangy

Acropora Nut
RS STAFF
PREMIUM
Unfortunately potassium is a reasonably new element on the block as it really only became looked at when ULN systems came about because they can be quite dependant on having the correct K+ levels for growth and colour. This means there's not a lot known about potassium (at least that I could find in any of my books or online) aside from it helps with colours (blues especially) and growth as it is a part of aragonite. It is it's use and addition in the structure of the formation of aragonite that makes it a strong trace element addition

Here are couple of exerts I found on potassium that are made by companies who produce K+ supplements:
Brightwell:
"In natural seawater, potassium is a non-conservative major element with a concentration slightly lower than that of calcium (~399 ppm vs. ~413 ppm, respectively). It is a component of aragonite, and regular dosing has, within the past several years, been implicated in improving the blue coloration of numerous varieties of small-polyp stony corals; the benefits of potassium supplementation are potentially two-fold, then: provision of an element that is 1.) incorporated into the skeletal material of corals and other reef-buidling organisms for purposes of growth, and 2.) incorporated into pigments that (presumably in the presence of adequate ionic iron) enhance blue coloration of small-polyp stony corals. The importance of potassium to marine organisms is most apparent when beginning to dose it in aquaria with depleted potassium concentrations and/or in which the sea salt mixture used is potassium-deficient; in such cases, changes in the appearance of many corals may be observed within the first weeks of regular dosing. Maintaining potassium within a range of 390 - 410 ppm is sufficient for long-term health, growth, and coloration of corals when all other physical and chemical requirements are met."

And Continuum:
"Potassium is required for formation of aragonite in scleractinians and required for color pigmentation in many corals, particularly small polyped stonies of blue and purple hues. Potassium can be depleted through heavy animal population and may be lacking in economy salt mixes. Continuum recommends that you maintain a potassium level of between 380 and 405 mg/L (ppm), a calcium level of between 410 and 450 mg/L (ppm), an alkalinity level of 7 to 11 dKH (2.5 to 4 meq/L), and a magnesium level of 1250 to 1350 mg/L (ppm). Note: Aquarists keeping SPS corals should consider keeping alkalinity at 7 to no more than 9 dKH (2.5 to 3.21 meq/L). Do not add Reef•Basis Potassium to buffering (alkalinity) products."

Both are direct quotes from their websites and I don't claim any of the information :)
 

Wrangy

Acropora Nut
RS STAFF
PREMIUM
Yep, it's also worth keeping an eye on corals and the system to see how it reacts but if you can test for it, it can be dosed :) With ~380ppm being the ideal concentration in the tank :)
 

Mike Johnson

Well-Known Member
I just read an article this morning about potassium. Unless you have large amounts of corals water changes should keep it in proper levels. Also, as you know, running a ULNS can deplete potassium. So, a low potassium level would indicate that you should step up on water changes.

Another article I read by a large coral dealer says that they only dose potassium and amino acids and depend on bi-weekly water changes for the rest.

Have you tested you new salt water?
 

mikecc

Member
All that Brightwell Aquatics stuff is sexy. You see it you want it. Masterpiece in marketing. I like their stuff tho.
 

DaveK

Well-Known Member
I always wonder about vendor supplied information. Are they trying to inform me or sell me something? If they are trying to sell me something, do I really need it?

Potassium testing is fairly new in the hobby. It's got me a bit interested though, because testing for it might be able to make things go better for the livestock. It wasn't that many years ago when calcium and alkalinity we not tested for. Yet those are considered important tests in a reef system.

Before adding any additives, my choice would be to test newly mixed SW and note it's level in relation to my reef system. If both are low, then it may be a question of switching to a better brand of salt. If only the tank is low, then a supplement may be in order.

Like anything else, go carefully here, and use your livestock as a point of reference. If that's doing well, don't fall into the trap of chasing numbers.
 

Bearjohnson

Well-Known Member
PREMIUM
RS Ambassador
If the goal is to replicate natural sea water and tests are available to aid in that quest, then I think it's also another one of those "how far are you willing to go" to achieve the best results.

I for one am all about eliminating the "controllable" variables within my system to help rule out possible issues that can and will arise if not under a watchful eye.

I'm far from an authority on anything reef keeping however, if I know that Calcium should be between 400-450, alkalinity 7-11dKH, magnesium 1250-1350 and salinity is 34-36ppt etc. then those are some of the controllable variables I can strive to maintain.

If my potassium test came back a lot closer to 400 instead of 280, then I'd look at it closer to something like PH in my tank which is always between 7.95 and 8.2 and say all is good and forget it.

Potassium is super easy to test and super cheap to add if needed so if it belongs at a specific concentration then that's just one more item I can check off my list as being "all good."
 
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