Potassium and Algae

[TheEngineer]

After receiving my Triton test results last week I discovered my potassium level was extremely low. I've started dosing potassium chloride and I've noticed that my potassium seems to be getting used up fairly quickly. I've been dosing slowly, should be adding about 5-10ppm per day. Having dosed for a 5 days now, I expected my level to be consistently rising. I tested on Saturday and I was at 320ppm according to my Salifert test. I tested again this morning and I'm at 300ppm. For an element that supposedly gets absorbed very slowly, that's pretty surprising.

I did some searching and came across this article that @Floyd R Turbo wrote on his scrubbing forum a couple years back: https://www.algaescrubbing.com/threads/dripping-potassium-iron.594/

This makes me think of two separate questions:
1. Is my bubble algae problem exacerbating my potassium problem? Similarly, am I exacerbating my bubble algae problem by dosing potassium?
2. Was this finding in my Triton test the result of my bubble algae problem and it is incidental to the issues I've been having? (I know that's a hypothetical that isn't answerable.)

 

[TheEngineer]

After receiving my Triton test results last week I discovered my potassium level was extremely low. I've started dosing potassium chloride and I've noticed that my potassium seems to be getting used up fairly quickly. I've been dosing slowly, should be adding about 5-10ppm per day. Having dosed for a 5 days now, I expected my level to be consistently rising. I tested on Saturday and I was at 320ppm according to my Salifert test. I tested again this morning and I'm at 300ppm. For an element that supposedly gets absorbed very slowly, that's pretty surprising.

I did some searching and came across this article that @Floyd R Turbo wrote on his scrubbing forum a couple years back: https://www.algaescrubbing.com/threads/dripping-potassium-iron.594/

This makes me think of two separate questions:
1. Is my bubble algae problem exacerbating my potassium problem? Similarly, am I exacerbating my bubble algae problem by dosing potassium?
2. Was this finding in my Triton test the result of my bubble algae problem and it is incidental to the issues I've been having? (I know that's a hypothetical that isn't answerable.)

Before anyone says testing error, I've repeated the tests.

 

[Lasse]

During 1.5 years I have had a negative trend according to potassium according to 5 Triton tests (se my thread for details - some of the lasts post - post 570) . No WC last year - and a lot of chaeto production. Potassium is normal a rather stable parameter in non zeolit tanks. I think that my growing of chaeto is the main factor for the lower levels of potassium.

Sincerely Lasse

 

[TheEngineer]

During 1.5 years I have had a negative trend according to potassium according to 5 Triton tests (se my thread for details - some of the lasts post - post 570) . No WC last year - and a lot of chaeto production. Potassium is normal a rather stable parameter in non zeolit tanks. I think that my growing of chaeto is the main factor for the lower levels of potassium.

Sincerely Lasse

Thanks for sharing. I do pretty infrequent water changes, so that could contribute to the low levels. I also run a low-nutrient system (not by choice, just circumstance), so that would drive the levels down too.

 

[Randy Holmes-Farley Verified Community Expert]

All photosynthetic organisms take up some potassium. So do all nonphotosynthetic organisms, although they may get it from foods.

The interesting thing (to me) is that there's no real reason to assume a tank will ever deplete in potassium, unless you are dosing nitrate and phosphate directly. Somehow the potassium to N and P ratio must be higher in the organisms in the tank than in the foods fed to it, and so K depletion may depend on what specific foods you feed, and how they are prepared.

FWIW, processing of foods that breaks open cells, such as freezing, may result in a substantial loss of potassium, if there is any rinsing.

 

[TheEngineer]

All photosynthetic organisms take up some potassium. So do all nonphotosynthetic organisms, although they may get it from foods.

The interesting thing (to me) is that there's no real reason to assume a tank will ever deplete in potassium, unless you are dosing nitrate and phosphate directly. Somehow the potassium to N and P ratio must be higher in the organisms in the tank than in the foods fed to it, and so K depletion may depend on what specific foods you feed, and how they are prepared.

FWIW, processing of foods that breaks open cells, such as freezing, may result in a substantial loss of potassium, if there is any rinsing.

I have previously dosed Potassium Nitrate, but haven't done so in quite a while. I've never dosed for phosphates. My nitrates read zero on my tests and from Triton. Phosphorous (or it may have been phosphates, I can't recall) were in the parts per billion on that test too. I have just one fish and she gets fed Blue Zoo's pellet food blend once a day.

 

[Lasse]

I dose nitrate on a regular basis. I only feed with frozen food - but never rinse.

Sincerely Lasse

 

[TheEngineer]

Back on this... I just tested again and I'm back down to 320. I stopped dosing Potassium Chloride a couple months back thinking my ocassional water changes would be enough. Guess not...

 

[Randy Holmes-Farley Verified Community Expert]

Back on this... I just tested again and I'm back down to 320. I stopped dosing Potassium Chloride a couple months back thinking my ocassional water changes would be enough. Guess not...

Are you using a two part for calcium and alkalinity?

If there's not sufficient potassium in it somehow, the method itself will reduce potassium even if there is zero demand.

The reason is that the method boosts salinity, and when you correct it back, everything, including potassium, drops.

If there's no potassium in a two part, the potassium will drop roughly 32% in a year if you are dosing about 1.1 dKH per day.

 

[TheEngineer]

Are you using a two part for calcium and alkalinity?

If there's not sufficient potassium in it somehow, the method itself will reduce potassium even if there is zero demand.

The reason is that the method boosts salinity, and when you correct it back, everything, including potassium, drops.

If there's no potassium in a two part, the potassium will drop roughly 32% in a year if you are dosing about 1.1 dKH per day.

I dose your two part recipe from BRS. It's really very minimal though. I'd have to calculate the volume (my controller is based on timing) but it is only a few mL per day.