Potassium Deficiency?

[Jennifer V]

I think my java fern and anubias might be showing signs of a potassium deficiency. The java fern is turning black in some areas and the anubias has some tiny holes in both old and new growth. I'm not the best photographer but photos attached. It's a 5g tank and I dose one pump of Easy Green once a week. I read that java ferns can suck up nutrients pretty quickly. Should I start adding something like seachem potassium or dose more Easy Green? 

[Scott P.]

I had the same thing happen. I started dosing a bit of potassium and the holes stopped.

I now add a teeny amount twice per week.

[Mmiller2001]

What are your Nitrates?

[Jennifer V]

On 8/27/2021 at 6:43 PM, Mmiller2001 said:

What are your Nitrates?

~20 ppm

[Mmiller2001]

On 8/27/2021 at 8:30 PM, Jennifer V said:

~20 ppm

Okay with that yeah you will need to find dedicated potassium fertilizer.

[Jennifer V]

On 8/27/2021 at 8:35 PM, Mmiller2001 said:

Okay with that yeah you will need to find dedicated potassium fertilizer.

Do you have one you like best? 

[Mmiller2001]

On 8/27/2021 at 8:37 PM, Jennifer V said:

Do you have one you like best? 

I do, but many view it as "scary", but Seachem has potassium premixed, just expensive. I personally use dry fertilizers, there's an extra step in calculating the dose, but it's dirt cheap. 

Seachem https://www.amazon.com/dp/B0002APILO/ref=cm_sw_r_cp_apa_glt_fabc_HWRMD04QKWWYTM3A7J2K

My choice https://greenleafaquariums.com/products/potassium-sulfate-k2so4-1lb-jar.html

5 bucks and will probably last you 2 years. But takes a bit more initial calculating.