[ray-the-pilot]

My personal experience with testing the levels of K in you aquarium would indicate that you cannot determine a K deficiency based on holes in your plants. You have to test the level of K in the water over time to do this.
I would not add additional amounts of K (beyond those recommended using standard dosing like EI or PPS) because that will result in severe imbalance in the ratio of KPN which is the basis of these programs. What is worse, if you kill off your plants the resulting plant material will give off high amounts of K into the water column creating even more of an imbalance? Sticking with the EI or PPS programs will make up any short term imbalance over time.

If you don’t stick to the program, you have no idea what is going on in your aquarium. If you want to do research that is great! Get a K test kit and figure out what is really going on in your tank.

 

[ray-the-pilot]

I respectfully disagree, K does not block nutrient uptake in small amounts like 36 ppm (or even way higher concentrations). The recommended levels on the fertilator are mere guesses at what the K level should be, and do not indicate harmful levels at all. This is certainly not the case with other nutrients like Ca, Mg, N, etc... these nutrients will cause nutrient uptake problems if dosed in too high a concentration.

I started getting K blocking problems at about 500 ppm concentrations.

Also, K is not an easy element to test for, and is notoriously hard to measure accurately, so any test kits that are cheaply available for K (if there are any) are going to be very inaccurate. I took my water samples to a lab and had them vaporized and tested the spectral emissions.

There are only a few plants that are sensitive to higher K levels (1 or 2, by my count) and these are not very commonly kept.

It is always best to use test kits to determine the nutrient levels in our aquariums and dose accordingly like you suggested, but the test kits available for potassium won't be able to do this. I believe the best course of action is to read the plant signs and dose a relatively modest amount of K to ensure they get enough.

I don't know about K blocking problems but I do know this: Nobody knows what effect excess K will have on all plants (including algae) and all fish. That means when you start fiddling with the program, you are conducting an uncontrolled research project using your tank as a guinea pig.
The worse part about such research is that its efficacy is just speculation. For example:
A patient goes to a doctor complaining about a cold. The doctor says eat two bowls of chicken soup every day. The patient follows the directions and in three days the cold is gone. Does that mean the chicken soup cured the cold?

I use a LaMotte nephelometric test kit. Using reference standards and my spectrophotometer it is easy to get accurate and reproducable results.

 

[ray-the-pilot]

The new leaves are gone. All the way down to the stems. Its just the new leaves though. The old leaves are still in tack and fine.

My SAE's regularly did that to my plants. They loved the central rossettes of my Amazon Sward plants. I always check KPN levels; so, I knew that there was no problem with nutrients. I though that it might be some form of bacterial rot. I didn't do anything but eventually it became obvious that the problew was from my SAE's. I lived with them for a few months and finally gave them away 2 weeks ago.

Hope you didn't add all that extra K.