Gone missing

Free to admit that I never worked too hard at the subject and have forgotten almost all I did know.
so I would like to stop feeding my tank nitrate and phosphate as I tend to be too rich already. Solution seems to be stopping the KNO3 and KH2PO4 but that leaves me lacking potassium which is where I'm seeing a lack already. Older leaves being robbed so that they die at the tips, etc.
Nitrates running about 40-50 and phosphate near 4-5.
So the big point is how much more K2SO4 might be needed if I drop the first two.
I have currently been dosing 1/8 teaspoon nitrate and less than 1/16 tsp phosphate.
Can somebody make a good estimate of how much K2SO4 would work to get a better balance going?

An explanation of how to figure this would be super but a plain short answer will work also. I've looked at the chart here:
https://sites.google.com/site/aquati...nt.of.mass.jpg
But that still leaves me not knowing what to do with the figures given!
Thanks for any help.

DutchMuch

Bumping this for you.

Gone missing

Thanks for the bump Dutch. Most likely one of those things that is so simple for the folks who know? I, however was working at an electronics shop at the time and just never really got into wanting to know much about the subject, never knowing I would want to know this much later. One of those little things that I plan to change if I get a second run at this life thing? Man, will there be some things i do different, next time!

hoppycalif

Excess potassium doesn't seem to do any harm, so a crude way to use K2SO4 is to replace KNO3 equally with K2SO4 - drop KNO3 by 1/4 tsp, and add 1/4 tsp K2SO4. There are also some calculators available that let you do this more exactly. For example: http://rotalabutterfly.com/nutrient-calculator.php

Gone missing

Okay thanks for adding the thought that potassium is unlikely to be too much and cause harm. I can "experiment" a bit more freely with that in mind.
A question on the calculator. I have looked at it but was unsure how to read it. I assume it expects one to be dosing Nitrate and phosphate when looking at the dose of K2SO4. So my question was If I was high on both of those (I am!) can I safely/ simply dose a one for one of K2SO4 to replace the potassium not dosed by dropping both N and P. I've been doing that for about a week now and see no change in the one plant that I am really working.
Situation? I have a 20 long with too much many weeds but it works well for me to use it to watch my nitrate and phosphate. Those two tend to be way too high in most of my tanks so the little tank is a better place to try to sort things out a bit. Red myrio, Java fern, Java moss, narrow leaf sag and different swords seem to grow very well. But at the same time, I have an anubia which does so little that algae tends to take over. Watching progression closely, I now see it tends to get what I thought was black spots of beginning algae, then develop yellow spots which progress to black holes which fall apart and the leaf dies. New leaves come on and seem normal for a time while the old dies.
I was working it as a potassium def. but not seeing progress.
Very hard, alkaline water Nitrate 20+, P of 1.0+, injected CO2 which should be plenty and other plants grow and spread but this one does this. Try not to look at the red and blue. Too many small fish to keep them out of the picture.
Open to suggestions, hints or even wild guesses!
Maybe it just isn't trying very hard?

New leaf and old leaf looking down through the water.

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