Potassium color?
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Randy Holmes-Farley
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No idea. Potassium ion itself is not ever colored in any compound, nor are chloride or sulfate, which should be the counterions used.
Presumably the color is some sort of impurity.
Presumably the color is some sort of impurity.
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I hope not. I know their marine scientist is not a chemistry whiz, but to think potassium permanganate is a good material in a potassium additive seems like something that even a marine scientist should know to not do.
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Well i added 52 grams to approximately 165 net gallons of this last night. I tested my potassium level at 350 ppm at 1.0265. The next morning, potassium only raised to 360 ppm. Why such a small increase? I tested newly mixed instant ocean and it tested 350ppm at 1.025.
Here is what they say on their website:
Instructions and Guidelines
Basic: Dissolve 2 grams (~½ teaspoon) of product per 20 US-gallons of aquarium water in 8-fl. oz. of fresh water; add every other day or as needed to maintain the potassium concentration within a range of 390 - 410 ppm. When used in this fashion, 1,200 g treats up to 12,000 US-gallons (45,425 L).Advanced: Create a stock solution by dissolving 5 grams (~2 teaspoons) of Potassion-P in 8-fl. oz. of fresh water (preferably purified); each ml of the solution will increase the potassium concentration (“[K+]”) in 1 US-gallon (3.785 L) of water by 1.7 ppm. [Reference: Each g of Potassion-P will increase the [K+] in 1 US-gallon (3.785 L) of water by ~129 ppm.] If initial [K+] in the aquarium is below 399 ppm, add stock sol’n at maximum rate of 10 ml per 20 US-gallons daily until desired concentration is attained, then dose daily or weekly as needed (see below). Maintain [K+] within a range of +/-10 ppm. Once desired [K+] has been acquired, measure aquarium's [K+] at the same time each day over a one- to two-week period to determine the daily rate of potassium uptake (i.e. the decrease in potassium). To determine daily dosing rate (preferable to weekly dosing): estimate volume of water in entire aquarium system (US-gal.); divide the daily decrease in [K+] by 1.7; multiply this number by volume of water in system to obtain daily ml of stock sol’n required to maintain stable [K+].
Caution: Keep out of reach of children. Not for human consumption.
Guaranteed Analysis
Potassium (min - max) 49% (490,000 ppm)Ingredients
Potassium chloride (anhydrous), Potassium sulfate (anhydrous)
Randy Holmes-Farley
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Maybe the test kit is not accurate.
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Its possible. But isn't 350ppm potassium in newly mixed instant ocean at 1.025 in line with what it should be? Or its off?
Any way to make a potassium standard to confirm my test with the potassium in brightwells product? I have a scale that measures .001grams.
Randy Holmes-Farley
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It's low. Should be closer to 400 ppm. I never added any to my tank using normal IO and that's about where it was when I measured by ICP.
Randy Holmes-Farley
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You can only easily make a standard if the kit will work in fresh water.
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400ppm is low at 1.025? I thought instant ocean was 400ppm at 1.0264?
Im suspicious if something isn't working right. I do waterchanges too about 30 gallons a month.
Im using Saliferts potassium kit. It expired in 2018! Worst case my potassium is 450ppm.
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Oh, sorry, Was thinking you were using 35 ppt.
IO and NSW at 1.025 should be around 379 ppm.
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Okay how about if i dissolve it in some water and measure the conductivity of it? I have that 40 year old hach conductivity meter i can use goes to 20ms/cm
Randy Holmes-Farley
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For what purpose?
It's not problematic to make a freshwater standard using the brightwell additive. The problem is knowing whether the kit properly responds in fresh water. So if you make a 400 ppm standard in freshwater and it reads 350 ppm, is that because the Brightwell additive is off (e.g., has moisture in it) or if the kit is off?
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Good points. The purpose is to see if their is actually mostly potassium salts in the ratios they say. Then i could assume that 52 grams in my 165 gallons should have actually increased it potassium from 350ppm to 400ppm and thus assume the test kit is not working but the supplement is.
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I got a new Salifert kit thats not expired, potassium measured 420ppm and the old ones reading 370ppm. The old one expired in 2018 and the new one expires 2023. I threw it away.
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Good to know. Thanks for the update!
