Reef Chemistry, K and Na importance

[Dmitri]

Question about reef chemistry and importance of these two elements

I was looking to purchase ion director which will test Cal Mg No3 Na and K parameters.

I have couple of questions about this.

1. What do corals use potassium (K) and sodium (Na) for? I know it’s a complex question and requires some understanding of how chemistry works. But I hope someone can shine some light on this for me.

2. What are some negative affects of lacking those elements in the reef tank or say we have too much of concentration of those elements?

Thank you.

 

[timeconsumer]

Sodium is one of the most prevalent ions in our reef tanks as sodium chloride is the main salt. I can't really imagine any particular need for testing sodium beyond maybe being concerned that 2 part additives on a tank without water changes is starting to skew your ionic ratios. Even then an ICP test once every year should suffice to handle that.

Potassium is a bit more complicated as it is tested for and dosed in certain methodologies, particularly the ones that involve zero water changes like Triton and DSR. Whether or not your corals actually consume any appreciable amount of potassium during their growth is not well understood. For most reefers that maintain small water changes it is likely maintained at reasonable levels through that.

 

[Dmitri]

Sodium is one of the most prevalent ions in our reef tanks as sodium chloride is the main salt. I can't really imagine any particular need for testing sodium beyond maybe being concerned that 2 part additives on a tank without water changes is starting to skew your ionic ratios. Even then an ICP test once every year should suffice to handle that.

Potassium is a bit more complicated as it is tested for and dosed in certain methodologies, particularly the ones that involve zero water changes like Triton and DSR. Whether or not your corals actually consume any appreciable amount of potassium during their growth is not well understood. For most reefers that maintain small water changes it is likely maintained at reasonable levels through that.

I do wish that these tested would be oriented on more useful parameters like phosphates and maybe iodine / strontium or even iron. For big three (alk, cal, mg) I currently use trident testing. It would be interesting to see both test results from ion director and trident to be compared side by side, good verification.

Maybe in coming years we can better interpret this data.

With this new ion director I’m definitely excited for No3 automatic tests!

 

[timeconsumer]

From what I understand there really is not a decent iron test out there to measure the low concentrations we need. Even ICP testing doesn't perform well with our needs there. Iodine is going to be extremely complex as well since Iodine comes in so many forms in our water that have different bioavailability. Automated phosphate testing I could definitely see useful, maybe even silicate. I think of all the automated testing bits the only one that I think is really a game changer is alkalinity since it's such an important test and it's a value that can change so rapidly, dropping as much as 2.5dkh in a single day.

 

[John Bowers]

You pretty much test sodium whenever you test total salinity. Yes corals and everything else use some sodium, but it is an insignificant amount. You pretty much only need to get total salinity right to get it close to ideal.

The GHL ion detector measures the levels continuously which is an advantage if you want to micromanage your tank, but for the most part if you have a healthy tank, the parameters will be incredibly stable, and not really need daily monitoring. Most of the ions will only change due to evaporation, and NO3 should be stable if you have a decent filter system. CA might decline slowly but not really enough to need to be adjusted more than once a month.

Unless you have tons of hard corals, CA will be stable. Same with all of the others possibly except Mg if you are dosing it to fight bryopsis.

If you have had your tank up for a year or more you should know about where the NO3 is at, and constant checking is usually going to be overkill. But for new tanks it may have some value.

Continuous checking of alkalinity and pH would appear to be far more worthwhile in my opinion.