Dosing Potassium?

[heff]

So my hygrophilia (corymbosa...? received it from jvision) has started to get small holes on some of the older leaves. From what I read, this tells me that I likely have low potassium in my tank.

I'm currently dosing KNO4, KH2PO4 and Seachem Flourish comprehensive. Should I be dosing K2SO4 as well? Looking at Epcor's readings, I see the average amount of sulphate is 60 ppm so should I really be adding more?

Ideally, I'd like to keep my water changes to a minimum but I'm wondering if I'm trying to create the impossible situation where my plants and critters are healthy and I don't have to do water changes every week.

If more info is needed about the tank, lemme know. I'll post a ton of it.

Any input would be appreciated as I'm pretty new to this and probably need a bit of guidance.

Cheers,

Hugh

[jvision]

There are other sources of K - you can try KCl (Potassium chloride). I have used KSO4 in Edmonton water for many years and haven't really noticed any detriment; however I do 50% weekly WCs. If Andre (he seems to know the most, there) is in at All Seasons, ask him if there is another easily available source for potassium that dissolves in water.

[Red]

In my reef tank I dose straight potassium from a Canadian Company Tailored Aquatics. Its in liquid form so it dissolves really easy and is relatively cheap. Might want to look into it.

[jvision]

There is no way it's strait Potassium - if it were, it'd be stored in a jar of oil and there'd be an explosion every time you added it to your tank.

Don't try this at home

[jewels]

I use have KCI, I find it dissolves readily in water.

Your KNO₃ is about %40 potasium. The levels (of K) in your KH2PO4 are negligible due to the smaller dose.

That being said hygro is a reported potasium hog

post #211

Hygrophila polisperma is a plant that consumes priority K. I have read that it is propose to be use as a bio-indicator of the lack of K. This is a mistake; the uptaking of K with this plant in your aquarium becomes bulky. You can put this plant just with water and potassium sulfate and it will grow well.

This post also specificly mentions the danger assoc. w/ sulphates

Without knowledge of your set-up specificly I would suspect lack of light.

[heff]

I've got a 14W aqua-glo over about 10" of water. The hygro leaves with holes are about 6" away from the light.

When holes start to appear, is it best to get rid of the leaf immediately?

[jvision]

I've never seen a leaf heal from K deficiency, so you may as well remove it if you don't like how it looks. That being said, the leaf will still photosynthesize so it's still a productive part of the plant.