newbie pmdd doser

[voodoo]

newbie to pmdd, just bought k2so4. going to try it after TMG finished. add 500ml water to 100g but it didnt disolve, can anyone tell me how to disolve it pls?

[PeterGwee]

K2SO4 is going to supply the plants only potassium and sulphate whereas TMG is supplying traces which is also needed by plants. Please do not think that K2SO4 can replace TMG..its a different thing altogether. Personally, I just dose it dry according to tank size...1/4tsp to every 20gallons of water scaling up and down accordingly.

[voodoo]

i understand that. what i mean is start pmdds after TMG finish.

according to Petergwee, u add it dry in to the tank, but it didnt disolve even in warm water how can it disolve in the tank and how the plant utilise it in crystalised form? not pinpointing, hope i didnt ask any stupified question. thks in advance!

[PeterGwee]

100g of K2SO4 into 500ml? Water can only hold a certain amount of salt content..beyond that, adding anymore and it won't dissolve. 100g of K2SO4 to 500ml is a bit too much so adding directly to your aquarium is the simple way out. Don't tell me your aquarium is only 500ml in volume or less?

[vinz]

Due to the large dosages, it's quite hard to prepare a stock solution for K2SO4.

I dissolve mine into a pail of water during water change.

[theodore]

K2SO4 is one of the harder salts to dissolve in water when you prepare a stock solution. I would not advice any1 to dissolve more than 30g of K2SO4 per 500ml. You may be able to add more if you use hot water BUT you will it precipitate soon after cooling.

[voodoo]

o now i understand, its due to the amount of water that it is intend to disolve in. i know any given amount of water can hold only certain amount of disolve salt, haha thks so much guys, will try to disolve k2so4 in smaller amount and bigger volume of water. thks again.

[checkerboard]

there is no problem adding it dry. I do that too with no adverse results. you may find some fish nibbling it though...

but that's because i am lazy!

[juggler]

I just dump the required amount in powder form to the tank. It will dissolve in a while. Saves the trouble of making a bottle of stock solution.

[voodoo]

for curiosity sake, i try to disolve the remaining k2so4 left in the bottle by adding another 500ml water and he he.. they disappeared! haha = all desolved!

conclusion, 100g k2so4 disolved in 1000ml water = *1ml = 0.92ppm potassium.( * calculation from chuck's programme).
to obtain the target of 20ppm potassium i need to pour in 21.391ml of the k2so4(provided no k in the tank), haha no need top up water for the evaporated tank liao!

note :above stated are only my experiment, not proven accuracy![]

[bclee]

FYI, the solubility of K2SO4 is 130g/L @25°C.

Solubility of other salts we commonly use:
KNO3 - 357g/L @25°C
KH2PO4 - 222g/L @?#176;C
MgSO4.7H20 - 710g/L @20°C

BC