Problem with N. japonica

[saugata]

Hi! All,

I am having a N. Japonica with me for the past 2 yrs or so. All thee while the plant was doing quite well and even now its doing good but there is a problem which has cropped up for the past couple of months or so. The problem is that the old leaves will develop small areas where the leaf will become very thin over a period of time and then finally holes will appear. The size of the hole will then keep growing and more number of holes will appear in the leaf.

Otherwise the plant is doing quite well as it is sprouting leaves @ 1-2 per week.

My tank has pressurised CO2, with medium lights and fert dosing in the form of KNO3, KH2PO4, Micros & Iron.

The appearing of the holes I took as signs of lack of "Potassium" and hence have started dosing 1/2 tea spoon of K2SO4 twice a week, once after w/c & second time on the 3rd/4th day. This I have been doing for the past 2 weeks.

I just wanted to check with experts if they have also faced something similar to this and what's the cause & remedy for this problem.

I am positive that the holes are not being created by snails.

Eagerly awaiting for comments from experts.

[StanChung]

Not an expert but I used to keep lots of types of Nuphar and this problem was quite common for me back then too.
The thing I would do is also add more substrate feed and you should notice improvement in a week.
What happens is this fellas roots would fill the whole tank.

Sounds like a K deficiency as well.

[saugata]

Hi! Stan,

Thanks for your reply.

Well, as of now I have already increased the dosage of K and is hoping that things should improve.

As a substitute of root tabs, can I put small laterite balls mixed with macros at the root of these plants? Will this help? I am asking this as getting hold of actual root tabs in India is quite difficult.

[StanChung]

Hi Saugata,
Yes that will work.

[saugata]

Hi! All,
Even after dosing Potassium (K2SO4) for the past 20 days or so the holes are still appearing. On last Staurday I removed all the damaged leaves and am now waiting for new holes to appear. I am actually at a loss to explain this. Somebody suggested that this is some kind of fungal infection & I need to put copper or Snail poison. But then since I have fishes like cardinals & rummy noses I don't want to take chances.

I had also put some laterite balls containing macros near the roots of the plant.

Any other suggestions?