k2so4 stock solution

[M0rph3us]

hi all i tried making my own k2so4 stock solution but encountered some problems..
acccording to http://www.csd.net/~cgadd/aqua/art_p...osage_calc.htm
i used 280grams of k2so4 with 1400ml of water.. so that every ml i add to my tank i achieve 0.5ppm.. but now.. my k2so4 like cannot dissolve.. is it normal? will it dissolve overtime???

[M0rph3us]

shld i further dilute it?

[David]

hi morph

if your are doing a pre-mixing solution, i dont think you need to dilute it any further. all you need to do is just before adding it to your tank dilute it further with a scoop of tank water.

I am no chemist but i think its actually best to keep all this stuff in their solid form and dilute when you need them.

[tawauboy]

try to crush the bigger lumps into powder first before mixing with water.
instead of keeping 1.4l of k2so4 solution, you can use chuck's calculator and key in 1ml as the stock solution volume. adjust the amount of k2so4 to achieve 20ppm. take the amount given and mix with tank water weekly.

[M0rph3us]

good idea man tawauboy.. why didnt i think of that in the first place[] no choice liao.. i just diluted it.... will follow yr advise the next time

[jacian]

280g in 1400ml of water, that would make a 90,000 ppm K soln. In my experience, I cannot dissolve the K2SO4 into a 50,000ppm soln, the most I could go is a 20,000ppm soln.

[Allen_1971]

I go with Jacian on this... Go with a lower concentration and dose more solution... higher concentrations result in lots of undissolved k2so4 which in turn means your dosing will be off.

[CK Yeo]

Of course it won't dissolve. The solubility of K2SO4 is 120g per litre at room temperature. You can push it to 250 g/l with boiling water, but it will probably precipitate out when it cools. For me, I just add them as dry powder. No problems.

FYI, KNO3 is about 350g/L... and so is KCl.