Potassium in tap water

[fishmeister]

Hello,
I have reviewed my local water report and did not see an entry for potassium content. Does this mean that the water has no potassium? Is potassium abundant in tap water and, if so, what is a "normal" amount ppm in tap water?

http://www.saws.org/our_water/waterquality/Report/2003_CCR.pdf

tia

 

[TankGirl]

Water contains all trace elements, to some degree, when you get right down to it, but there will be so little potassium you probably could not measure it. Potassium would not be added to the tap water. Phosphates are often present in tap water, generally due to farm fertilizer runoff into water systems, but this is not always true.

 

[madasafish]

Hmm... They do have a lot of things listed there.

I can only think that Potassium is sufficiently benign in large qualities, sufficiently insignificant in quantity in your water, and not the focus of Federal law. Most of the substances listed there (e.g. Xylene, Lead) can be very toxic and have been the substance of lawsuits in the past.

Some ppl will say: "But potassium can be toxic in high quantities!" True, but I'm guessing nobody's ever sued a municipality for high potassium content in their water... thus San Antonio doesn't report Potassium.

Believe it or not, they don't put these reports out for fish keepers/breeders. Shoot! They should! In which case, they'd also mention dissolved CO2 levels and the water's suitability for certain fish!

I'd just dose for potassium myself, because even if it is there in the water, it'll be used up quickly by your plants since there are (presumably) quite a few of them in a small space.

I don't know a usual ppm for K in drinking water, sorry.

 

[trenac]

When I tested for potassium in my tap water the readings where a little over 1ppm but not over 2ppm. My test kit recommends not to go over 2ppm in your tank. However my tank water is way over 2ppm and will not go down. I was told not to worry much about it since the plants use it up and they are doing very well.

 

[fishmeister]

Thanks for the replies...I have purchased some nutrients, KSO4 being one of them and I have read that potassium test kits are unreliable. I have read that the best way is to find out how much of each nutrient is in the tap water and then dose accordingly. I guess an assumption of 1 ppm would not be bad to start out with. I can then dose to recommended levels and increase or decrease based upon how the plants respond.

Again, thanks for the responses.... 8)

 

[Guest]

The recommended level of potassium in the planted tank is actually more like 20 ppm. However for a couple of reasons I don't run levels that high, but they are over 1-2 ppm.

 

[betowess]

Many folks dry dose k into their water changes as a standard procedure. Check out Rex's FAQ for more info and/or use Chuck's nutrient calculator which you can download here for dosing calculations. http://www.csd.net/~cgadd/aqua/art_plant_aquacalc.htm