Interesting thread indeed!
I also had some stunting problems and curly leafs (especially Alternanthera) now and then on some species for a long period (1-2 year).
I’m using the EI method with 50% wc per week and do not measure any nutrients at all. However, I put a lot of focus on measure and sampling data of the CO2 in the tank to make sure I have enough every single hour every single day. I have been dosing in the range of: 10-15 ppm N, 1-4 ppm P, 10-15 ppm K, and 0.1-0.2 ppm Fe (Micro+). I have soft water from the tap (20 Ca, 4 Mg) and I’ve tried to boost up to quite high levels without success.
Five weeks ago a bought some test kit’s (
http://www.bluesboy.se/viewimage.php?id=646 ) and started a new approach with much lower nutrient levels and the tank is now running very well without stunting plants and curly leaves.
My new dosing regime:
After wc I add:
6 ppm N + 4 ppm K from KNO3
5 ppm K from K2SO4
0.25 ppm P from KH2PO4
No extra Ca/Mg is added at all.
Now my remaining issue which confuses me a lot – trace elements.
I have to add 0.2 ppm (no more no less) from Micro+ every single day. I also have to add it in the morning otherwise the level is zero after one night. Ok, I know test kits are sometimes confusing and messing things up but I trust the JBL quite well. It shows me exactly what I’m dosing!!
I’m just wondering where all the traces (Fe) are absorbed? By the plants, filter, substrate – who knows? I have checked the filters and there is no miscolour from Fe. I can hardly believe that the plants uptake is so big. Substrate - hmm...maybe.
By in fact, the tank is now running week after week very well without algae:
http://www.bluesboy.se/viewimage.php?id=669