Milan Posted August 31, 2005 Report Share Posted August 31, 2005 (edited) I am not sure, but I think my Hygophila Polysperma and Wisteria are showing signs of potassium deficiency. Older leafs are getting pale-yellowish with brown spots and some decaying at tops, while younger ones are fine. All other plants are fine. I'll try to post a picture tonight. I am dosing 0.9 ppm of K in the form of K2SO4 every second day. NO3 and PO4 are stubborn at 5 ppm and 1 ppm. Water changes are done weekly ~30%. I have a feeling that K may be the limiting factor. Well, now I'm wondering if I increase the dosage of K2SO4, lets say to the same amount of 0.9 ppm but daily, and I misjudged this, is there any danger of overdosing potassium? Garhan, are you there ...? Edited August 31, 2005 by Milan Quote Link to comment Share on other sites More sharing options...
andyg Posted September 1, 2005 Report Share Posted September 1, 2005 Milan, you can safely dose 3-5 ppm of K2SO4 every couple of days without overloading your tank. Target levels for K is around 20 ppm, NO3 10-20 ppm, PO4 .5-2 ppm. I try to maintain a 10:1 ratio on NO3/PO4. Hope this helps, Andy Quote Link to comment Share on other sites More sharing options...
Milan Posted September 1, 2005 Author Report Share Posted September 1, 2005 Thanks Andy. Tonight I found my H.P. worse than last night, so I am going to up the potassium, effective immediately ... Here are some pictures, as I promissed ... Quote Link to comment Share on other sites More sharing options...
Milan Posted September 1, 2005 Author Report Share Posted September 1, 2005 Here is another one ... Quote Link to comment Share on other sites More sharing options...
Milan Posted September 1, 2005 Author Report Share Posted September 1, 2005 And another (sorry, it doesn't let me put all pictures in one post) ... Quote Link to comment Share on other sites More sharing options...
Milan Posted September 1, 2005 Author Report Share Posted September 1, 2005 Well, ... something came to my mind what really angries me. How could I neglect the simple math. :bang1: Here is the "magnum revelation": I'm dosing 0.9 ppm of K every second day. This is the only source of K. This, providing that there are no plants or anything to consume it, makes for about 2.7 ppm total at the end of the week, and here it comes the water change ... !!!! Not even in the wildest dreams I can reach the 20-30 ppm target ... Now, the question is, how aggressively I can ramp it up? I was thinking about 3 ppm/day... That's about 21 ppm before the weekly water change. Or perhaps 2 ppm/day and cut down with the water changes to bi-weekly. Any concerns ...? Quote Link to comment Share on other sites More sharing options...
Garhan Posted September 1, 2005 Report Share Posted September 1, 2005 Milan, hello this is definitely a lack of K issue. Most of the readings I have come across show a variance in the K ratio of 3 to 4 times greater. K to my understanding cannot be over dosed as the plants will only use as much as they need to help them in there up take of N and P. There will be some new research matierial specifically out on K issue late next month. Currently there tests show the more K the better. As always if there is to much dosed of anything then the w/c is in order. Garhan Quote Link to comment Share on other sites More sharing options...
Milan Posted September 1, 2005 Author Report Share Posted September 1, 2005 Thanks Garhan, I ramped up K2SO4 to 1.8 ppm/day which is 4 times more than it used to be. I may even increase it further if I dont see NO3 and/or PO4 dropping to 0. Any suggestions when can I expect the change in the two? I believe the plants will recover, except for already damaged leafs .. right? BTW, I replied to your PM. Quote Link to comment Share on other sites More sharing options...
Garhan Posted September 1, 2005 Report Share Posted September 1, 2005 Milan, there is a newer ratio out for NPK and that is 7:1:10. Ther is more coming available next month when test results are available. Quote Link to comment Share on other sites More sharing options...
Milan Posted September 1, 2005 Author Report Share Posted September 1, 2005 I'll keep my eyes open ... Are you talking about some commercial fert or something else ?? And who is doing the testing ? Quote Link to comment Share on other sites More sharing options...
Garhan Posted September 2, 2005 Report Share Posted September 2, 2005 Not commercial it is a fellow that is completing his masters on aquatic macropyhtes.He makes to much sense to me at this time. But we will have to see how his thesis turns out. Quote Link to comment Share on other sites More sharing options...
Garhan Posted September 2, 2005 Report Share Posted September 2, 2005 Oh yeah and expect signs of results in about 2 to 3 weeks on the newer growth. But pay close attention to what will be then old growth on your plants. Quote Link to comment Share on other sites More sharing options...
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