Do I thaw my mysis shrimp and throw away the fluids or not

[Randy Holmes-Farley]

Measurably? I can't imagine that's the case, given the levels of K in saltwater and how much cellular fluid we're talking about.

If K in the system is measurably affected by mysis fluid, I would think that N and P would also be to very roughly the same degree, and those are in SW at levels that are about 10x-100x less than that of K (so, the argument not to add the fluid to the tank is much stronger).

You cannot imagine it?

Let me assist your imagination. lol

Why do you believe some folks see potassium decline and others do not?

I’m not claiming this is the only, nor even a proven mechanism, but it is a simple and logical explanation.

In organisms, from bacteria to man, potassium is generally contained inside of cells, and those concentrations are typically far higher than in seawater. In people, potassium is 98% inside of cells where the concentration is about 140 mM. That equates to more than 5,000 ppm. Bacteria are similarly high inside.

Freezing is known to break cell membranes, which would tend to release the internal potassium to the extracellular fluid. On the other hand, freezing does much less to release the N and P that is bound up in large structures such as the cell membranes, proteins, dna, etc.

Thus if one throws away the frozen food liquid, one may be discarding relatively more potassium than N and P.

When that added N and P is used to grow new tissues in fish, corals, etc, the newly created cells will have to take up potassium from the water.

Thus, unless one adds the same basic amount of K per N and P via foods, there will be a trend to declining potassium.

IMO, it is a highly logical and straightforward hypothesis. I have not seen any data to support or refute it, but it is easy to imagine how it might happen.

 

[tuscani]

I add to feeder cup frozen as is right from freezer

 

[Malum Argenteum]

At 5000 ppm, to raise the system water K level by 5ppm one would have to add 1/1000 of the system volume in mysis fluid -- 100 ml in a 100 liter tank. That supports the 'measurable' comment, I think.

 

[Randy Holmes-Farley]

At 5000 ppm, to raise the system water K level by 5ppm one would have to add 1/1000 of the system volume in mysis fluid -- 100 ml in a 100 liter tank. That supports the 'measurable' comment, I think.

I don’t believe that calculation says it is not a cause of depleting potassium. We are talking about effects over months. Potassium does not change in a day.

In any case, if one ascribes a potassium decline to growth of organisms, and that growth is driven by N and P in foods, then clearly there is enough internal K from that amount of N and P in tissue to be detectable.

If the foods bring in less K than expected based on the N and P, it seems clear to me that the this would be the cause of declining K. The remaining question is whether the lost fluid is the reason for the low K in the foods relative to N and p. It may not be, or may only be part of it.