Potassium Deficiency ?

[Laserbeak]

Hey folks, new to the forums /bow as far as writing, but have been stalking...err heh I mean following...umm..watching? READING! (ha!) what you all have wrote in this forum for sometime.

I am pretty sure It's a potassium issue i am having ( or lack thereof) but I just wanted to post some pics to see if anyone can confirm my suspicions.

I apologize for the photos they were taken with my smartphone.

My setup is a 20G with stock overhead fixture with Aqua Glow T8 15W and a Marineland® LED Bright Lighting System ( i realize the LED doesn't contribute to the growth of my plants. i just wanted more light.) Both lights are on a 8hr timer. 12-8pm

I use Seachem Iron and API liquid fert (el cheapo version of flourish) as well as excel.

There are no fish in this tank as I did a reset of my tank after an ich issue ( housemate got fish from her friends) while I was away for a couple of weeks..yay me)

So there has been no fish in this tank since the reset some 5 months ago. (as well as the LFS here in the city has let their aquariums go to pot and petsmart tanks are garbage)

The bamboo you see in the background was added a few weeks ago while i was still having this issue so i know the bamboo is not a factor.

 

[Laserbeak]

one more pic that might help

 

[hondaboi]

This is what ive learned regarding chinese bamboo.. as long as you don't submerge them all the way & once in a while spray the top part (bamboo leaves or the top bamboo stick) atleast once a week it will grow as it is supposed to...

 

[Bert2oo1]

one more pic that might help

I'd certainly start with potassium. If in a few weeks it doesn't improve after dosing then I'd be looking at maybe traces?

It is most likely potassium tho. I'm pretty sure products like flourish etc are pretty low in potassium.

 

[PerfectDepth]

Which API product? If it's Leaf Zone, it contains potassium already. Leaf Zone will only cover only potassium and iron, though, and you don't need the seachem iron if you're already adding Leaf Zone. You'll need some regular Seachem Flourish to provide micro-nutrients. Without having any fish and not much for fertilizers, it really could be anything including a phosphorous or nitrogen deficiency. This article will explain everything plants need:
Introduction to Fertilizing the Planted Tank - Aquarium Advice

 

[Laserbeak]

Thanks for the reply folks. I will take a look into a few things you said .
Yeah it is API leaf zone that I use. I just couldn't think of the name of it the other day.

Regarding the bamboo, yeah they are well over a foot tall with the tops sticking 6 inches out of the top of the tank. I do moisten the leave up occasionally.

Thanks again Folks, I appreciate it.

 

[Laserbeak]

Quick question

I have been doing 20% weekly because I assume that if no new water is being added, then the plants are using up what they need out of the water and I'm left with water that has nothing positive for the plants.

Not sure if that's true or not but i figure better safe then sorry.

So my question is.. since i have a planted fishless tank, how often would you suggest i do water changes? or is my thinking about the nutrients in the water being used up WAAAY out in left field and I don't need to do any water changes?