potassium nitrate

[medge00]

if you're dosing postassium nitrate to get your nitrates up to desired levels, is it really necessary to dose something else for postassium as well?

just curious.

 

[gone fishin]

Depends on how much potassium your tank needs, usually yes.

 

[Steve Hampton]

It really depends on how much potassium nitrate you are adding for nitrate. If you are adding potassium nitrate weekly then it should provide more than enough potassium. If you are only adding it (potassium nitrate) on an occasional basis and most of the plants nitrogen is coming from fish waste and nitrification then you should add a weekly dose of potassium in the form of potassium sulfate or potassium chloride. Note that unless your water is soft you don't need to be overly concerned about overdosing potassium. Personally, even though I add lots of potassium nitrate throughout the week, I also add potassium sulfate each week after my water change...this is likely unnecessary but since I have moderately hard water the extra amount if potassium won't become problematic. Several people do report problems with calcium "lock-up" and the associated leaf deformity when adding too much potassium in soft water...it seems that the calcium to potassium ratio is at least semi-important. BTW, I dose 15-20ppm of potassium via potassium sulfate per week in addition to what's dosed with my potassium nitrate additions.

 

[travis simonson]

On your suggestion Steve, I've started dosing at least 20ppm of potassium sulfate weekly because I don't need to dose any KNO3 at all for nitrates as the fish are more than happy to supply this macro themselves. I haven't had any problems at all and have noticed that pinhole damage to my older cryptocoryne leaves has all but disappeared. Excellent advice as always

 

[medge00]

thanks y'all, i think i've got it straightened out now.

 

[malkore]

Only thing I want to add is that you don't have to measure potassium levels. If you dose 15-20ppm once a week (after water change) that should keep you at a reasonable level.