That looks pretty healthy, just pinch off the old yellow leaves when you give it a thin.but my Amazon Frogbit persists with having a few yellow leaves
@dw1305 sorry for the silence - turns out being a teacher is hectic right now!
Thanks! When I get some time I plan to read up on EI and do it properly. In the meantime, no I'm not dosing Mg - might I need that on top of TNC? I'm a chemistry teacher so should be able to get some on the cheap Is Epsom Salts the recommended form?They look a good size so maybe Nitrate isn't the issue. Are you adding any Magnesium? To be fair I would probably still go back to complete. The water report isn't cast in stone just an average of when they were testing. Over time with just partial water changes in a well planted tank it won't take long to burn off that nitrate.
I bet, my wife is a teacher, for the last couple of years she has been mainly working as a TA, but in 2020 a lot more time has been as a teacher and a lot less as a TA.@dw1305 sorry for the silence - turns out being a teacher is hectic right now!
Try @AverageWhiteBloke 's suggestion, the plants look OK and a bit of extra Mg isn't going to do any harm. Your water won't contain much magnesium <"for geological reasons">, most of SE England has chalk aquifers, and chalk doesn't contribute much other than Ca++ and HCO3- ions.Yes buddy epsom salts is the one. I've just had a quick look at the TNC stuff and there is the same amount of magnesium in both lite and complete albeit in small amounts. My understanding of using Duck weed to look for deficiency is new leaves would be iron, old leaves potassium and nitrate which the plants consume the most of. That just leaves magnesium which effects old leaves also.
Yes, "Epsom salts" (MgSO4.7H2O) and ~10% Mg.I'm a chemistry teacher so should be able to get some on the cheap Is Epsom Salts the recommended form?
<"Liebig's law of the minimum">.There is a law whose name escapes me right now, liebrig or something or other? It dictates that plants need all the trace elements plus N,P and K to form healthy plants if any of the above is missing it weakens the plant, look at it like building a wall without sand.