KCl solubility

[fish_4_all]

Well I have found a source for it but now I need to know a little about it. I have gregs dosing calc but the stuff I may get comes in a compressed pellet form. I know this throws off the measurements because I don't have a scale to weigh it.

According to gregs I need to add 1/3 tsp. Can anyone give me more infomration as to how to possibly calculate that in a compressed form? I know I can't exactly overdose K but the chloride has me wanting to make sure I don't poison my fish accidentally.

I was also wondering. Being it is already in a compressed form would it be advantageous to try and dose it under the plants like a root tab?

 

[Zezmo]

Try using a mortar and pestle to crush it to a powdered form first.

 

[jsoong]

I wouldn't dose it as a root tab. The Cl- is same as in table salt (NaCl). Plants don't do well with salt, so a heavy dose of that near the roots will prob. kill them.

I would worry more about the plants with KCL overdose. Most fish can take 0.3 g% salt <my golds can take up to 0.9> and you won't get up to that Cl- concentration unless you use a quater cup or so of KCl in 10 gal. Most plant wiill be dead at 1/2 that level. (Learn that the hard way using salt to treat ich.)

With the dosing, the best way is to weigh the KCL. Without a scale, you can:

1. Measure the pellet (with a ruler) & work out its volume - if all pellets are uniform & big enough to measure. There will likely be a bit of rounding error unless you own a caliper.

2. Crush a know number of pellets into a powder & measure its volume with measuring spoons. <Coffee grinder works great.>

3. If you have a graduate cylinder, you can fill the cylinder with some oil (so the KCL will not dissolve into it), put in a known number of pellets & measure the increase in volume of the liquid.

Once you know the volume of a single pellet, you can dissolve that into a small volume of water to make your dosing solution.

eg. If the pellet is 1 tablespoon in volume (=15 ml), you can dissolve that into 150 ml of water. 1/3 teaspoon = 1.66 ml .... so you can dose 16.6 ml of your stock solution to equal the 1/3 tsp. << You are basically making a poor man's version of Flourish K! >>

Since KCL is inert, you can store your stock solution indefinitely.

 

[fish_4_all]

MY LFS doesn;t have the sulfated potash but they have some that is K2O. As long as it is soluable in water would this work?

If it will would one of the chemistry brains minding helping me figure out the doage?

 

[jsoong]

K2O? That is rather alkaline, not sure if that is good in a tank .... anyone know?

However, the archaic way of measuring fertilizer content (ie the NPK labeling you see) expresses the K content in K2O (and P as P2O5). This does not mean that the fert actually contains K2O. Apparently, they measure the K & P content by burning it & weighing the resulting oxides. <My hydroponic fert mixes are all labeled like this.>

FWIW, K2O is about 83% K by weight, while KNO3 is about 44%. So you would use 1/2 of the KNO3 amount if you are actually adding K2O. <This is assuming that your KNO3 dosage is based on its elemental K content, & not the NPK nonsense.>

 

[fish_4_all]

Well it sounds like the K2O is going to be a little bit of a pain to wrok with so I won't use it. Beginning to think I should just wait and save some and order from Gregs again. I have used so little of the KNO3, KH2PO4 and CSM+B that all I need is the K2SO4. Maybe it is time to order some calcium also, maybe the GH booster but I should have plenty with the added Crushed coral for both Calcium and Cabonate. Oh well, maybe I will try the KCl and see if it has any detrimental effects on the plants.