How do you know how much potassium to add?

[druxboyz]

the potassium kits seem pretty expensive. do all you plant growers use that kit?

my nitrates are 12.5ppm already due to fish, so i dont add KNO3 anyways to receive K.

I dont know how much potassium i currently have in my tank, is there any other way to find out?

Some people say that its impossible to overdose on K, should i just be adding weekly doses and just assume that things are in the correct range if my plants are doing well?

 

[mrV]

Nope, I haven't buy those tests - I think they are waste of money. I have seen many times that KNO3 is recommended in tank where are fishes. I don't see any reason to use KNO3 if you already have NO3- in your tank. I use K2SO4 instead.

10,5g K2SO4 per 500ml water => when K2SO4 is dissolved, I take that solution 10ml for every 100 liters of tank water. I use K2SO4 as one of the main element in PMDD. My tank is heavy planted. (As you can see it from this image.)

Some people say that its impossible to overdose on K,

Hmm... interesting...