kekon

Recently, I've had the same pymtomps of K excess as in the past (described in "KNO3 - too much potassium" thread) Some time ago I had 27 ppm of K and most of leafs became deformed and curled and the growth of all the plants was stunted. After decreasing K and doubling Ca and Mg levels plants become healthier (Ca from 13 to 26 ppm, Mg from 4 to 8 ppm). A few days ago I saw the same issues and measured K level in labolatory. This time is turned out to be 28 ppm of K and, leafs became deformed again. Maybe one can have high K levels but it must be done together with appropriate Ca and Mg concentrations. The question is: how high ? It seems to me it would be safer to dose K only during water changes from K2SO4. Dosing X ppm of K into 50% changed water ensures that we will never exceed X ppm of K. When dosed only from K, I never know what is the K level in my tank. When dosed from KNO3 and K2SO4 there will always be an excees of K. That's why I prefer do dose NO3 from CaNO3 on daily basis and K from K2SO4 at water changes.

plantbrain

Why can I have 50-100ppm of K+ and not see this then in the same plant species??

You did not test everything, only things you had preconcieved notions about.
There is another confounding factor in your tank, I can tell and assure you, it's not high K+, something I had for over a deacde with some 200 plant species and never had an issue as did anyone in the SFBAAPS group, some of which had levels over 100ppm and won the AGA contest with supposed sensitive to high K+ plants.

Bark up another tree.
You can still solve the plant issue by adding less, but it's an indirect effect ocurring, not directly related to high K+.

Regards,
Tom Barr

kekon

Well, I'm very confused about the problem because I don't have an idea what may be the limiting factor... Now I have 10 ppm NO3 and 1 ppm PO4 and plants really look much better with lower levels of K. I realize high K levels may not be harmful but I can't find what causes my plants to be sensitive to higher K levels.

plantbrain

Well, you rule things out step wise.
You rule things out rather than going right for the cause.
Eventually you find what it might/must be.

Then you repeat it and talk to others that have done the same thing.
I do not know what you or other folks that have claimed this effects occurs, but I do know 100% that it's not due directly from excess K+ and it's not sensitive thing either, I've gone all over the place with high/low K+ values without ever having such issues.

For something to be true, say someone's theory about K+ stunting plants, it needs to be repeatable by others specifically.

If not, then something esle is going on with your tank and the high K+ is simply a correlation, not a cause for the issue.

People use to say that PO4 caused algae blooms. But I added it and never found that to be true.

Likewise here with higher K+ causing stunting, I added higher K+, and had no stunting.

This does not tell what causes algae, or the stunting and K+, but it does tell you it is not K+.

It must be some other effect, some other nutrient, CO2, low Mg etc.

Regards

Tom Barr

davej

I had a similar problem in the past, and the answer for me was Calcium Carbonate. After using the calcium the new leaves stopped growing in deformed.
My 2 cents

kekon

As far as PO4 is concerned I'm sure it's not main cause of algae blooms. I add much PO4 and plants love it and I don't have problems with algae (the more PO4 and NO3 I added the less algae I had)
But when it comes to K, I suspect it may something wrong in K:Ca:Mg. On the whole, things go better when Ca and Mg are higher. I don't know yet how high Mg should be; now I have 5 ppm and 25 ppm Ca. Ca is dosed from CaCl2 and CaSO4. I wasn't able to dissolve CaCO3 in the water even in one hevily enriched in CO2. I managed to dissolve only a few grams of CaCO3 in 250 ml of water mixed with 2 ml of HCl.

plantbrain

But it's nothing to do with K+....................
Nor ratio thereof..........

It might be due to low Ca, it might be due to low Mg........
Plants do well with good GH, even the few soft water water plants.

Simply making sure the GH is good for both Mg and Ca will take care of most problems, but it's not due to inhibition or blockage. We all know this in the Bay area where we have super soft water, along aside medium and hard waters.......most of us add more GH in most all cases.

Decent CO2 can prevent curled leaves in a number of plants.

Regards,
Tom Barr

kekon

Thanks Tom Unfortunately I'm not as experienced as you are (and probably will never be), that's why I have so many doubts and fall in confusion...
If it isn't a secret, could you tell what levels of Ca and Mg do you have in your tanks ? (I understand the even I know that it doesn't mean it would help my plants grow better)

IUnknown

This is a chronic problems that I have had in my tanks for years. It just started in my new tank the other day. I've relocated from the bay area to orange county, so it must be something in my fertilizer routine that I'm botching up. I had some problems with Co2 the week before, don't know if the stunting from the poor Co2 was delayed a week? My routine for the 20 gallon is,
48W t5
Fr water change
sat 3 mL Flourish (No3 out of tap is 15ppm)
sun 8ppm No3, .5 ppm po4
Mon 3 mL flourish
tue 8ppm No3, .5 ppm po4
wed 3 ml fl
thur nothing

Maybe I should try something other than KNO3. I don't know what I'm doing differently than anyone else. Old notes I might try out,

"I also noticed that the new growth was stunted. After reading about possible causes, I think that I might be running Po4 a little lean (no Po4, no No3 consumption)."

http://www.aquaticplantcentral.com/f...-gallon-2.html

plantbrain

I shoot for a decent GH, 5 or higher in general, but if you use soft water, then I add about 1-2 degrees.

I add 1 degree of general GH booster no matter what, the extra will not hurt and rules out any Ca/Mg etc issue.

A nice balanced GH booster will address that, you can make your own also.

Regards,.
Tom Barr