Hi all,
I have been meaning to make this post for a while - so it kind of "journals" my thoughts:
Major points:
I used to remineralize my water with 15 ppm CA, 5 Mg, 40 ish potassium, and 2 KH added.
I had no health issues except Rotala crunching. I was unsatisfied with the crunching - it seemed "wrong" - but maybe it was "right" ... it also had much darker veins than it does now.
After stripping my water of the remineralization, the crunching stopped yet the rotala paled.
I added magnesium (with a daily dose), and the rotala cleared up and there was no crunching. But Darrel's duckweed index proved yellower than I would have liked.
I began to wonder why ADA (and other lean dosing regimes) could have such low GH in their tanks and show no sign of magnesium deficiency whereas I had it in my tank (I have low GH tap water).
I later realized that GH was suggested as part of EI (and when I stopped "remineralizing" my water ... I stopped adding GH booster).
I decided to front load - and added all the magnesium all at once on Water change day. The plants (especially Pogo) greened up more.
Then I saw some weird "hooking" on the crypts and anubias - and the anubias was coming in very yellow.
I added Ca bringing me up to the 20ish range in the tank.
Things looked better - the rotala colored up nicer. At this point I was 20ish Ca and 12 ish Mg. I read that plants color up in higher GH's from Tom Barr. But look at ADA.
I realized that although the plant may only need "tiny" amounts of these, we still need to have enough in the water so that the plants "get" them ... whether that is a probabilities game or not. I think it has to do with the number of ions in solutions.
This led me to wondering if you can dose EI in low low GH water (maybe 1?)... but when you dose the "right amounts" it puts you at around 3 GH ... and that is enough. If we reduce the number of ions, I think the minimum GH required for healthy plant growth decreases. And this is probably down to ionic interactions.
STILL Darrel's duckweed told me that I needed something more. I read over and over that I would have "enough" potassium by dosing EI levels of KNO3. But that daily business didn't work with Mg ... so why would it work with K? Something about these positively charged species.
So I front loaded my booster with equal PPM of Potassium to Calcium. On water change day, I added 9, then 12, and have now abandoned the measurement approach and embraced Clive's this is "food not medicine" ... so I have been slowly increasing the potassium every week by 1/4 tsp.
So, if I had just added a pre-made booster, dosed EI properly, and dialed CO2, everything probably would have been fine - HAH! But I learned a lot doing this.
After the potassium addition, my duckweed and rotala greened/un-yellowed just enough that I am satisfied. I am going to continue adding potassium until I see an adverse effect. I will probably also stop at some point and add more Calcium. Also, I'd like to dose a lot more magnesium so that Mg > Ca in ppm and see what happens. The constant will be EI dosing. Then I probably have to abandon EI and go lean and then do all this again 🙂.
I also added some Rotala Macrandra mini-butterfly, some limnophila aromatica, and some rotala bonsai to see what happens to some more sensitive species.
I still have no clue what caused the crunching -- maybe it was the KH? Or maybe it was "right" and it was trying to flower.
Josh
EDIT: I backtracked on increasing my EI dose and left it at constant EI levels.
