Tom,
I followed your recommendation for about a week except I didn't add the KH2PO4.
After 2 days I noticed an increase in green algae. So now I have removed my 2 driftwood locks, which smelled bad when I took them out.
When I measured my NO3 concentration after 3 days of the first dosing it still showed 0 on the test kit so it seems my plant absorb it really fast.
In addition I have ordered now a PO4 test to see what those show.
My water is as cloudy and green as it possibly could be. I did 2 x a 50% water change and have added since only some trace elements, CASO4, MGSO4 and some iron mix. The hair algae have slowed down, pH stable between6.4-6.6
In addition I ordered a Diatom filter to get rid of the algae.
Any other recommendations would be highly appreciated.

Thanks

Wolfgang

Wolfgang, that is like saying I ate balanced meals for two weeks, except I didn't eat any vegetables. You need to decide whether you want to fertilize by trying to use test kits to tell you what to add, in which case you absolutely must calibrate the test kits, or if you are willing to use a dosing system like EI, which doesn't require testing, but which requires dosing all of the nutrients the plants need. Right now you are trying to design your own system on the fly, and that just doesn't work.