So, I’ve a hard water tank and this chlorosis thing is a bit of a pet project for me at the moment.
I note your micro info doesn’t actually advise on whether or not the Fe is chelated at all so that’s probably less than helpful for you (unless it mentions this somewhere else on the packet?)
EDTA is stable up to 6-6.5ph and DTPA is stable to up to a PH of 7-7.5 (depending on source information) though note that the higher it gets, the less iron is available, and EDDHA goes up to a Ph of 9 or thereabouts.
Your tank it seems will exceed a Ph of 7 when Co2 is off, so, even with DTPA, by the morning after your micro dose, it could be that most of that Fe is no longer available.
EDDHA may solve that issue but the stronger the chelate, the tougher it is for the plant to access it. (And it’s pink😫)
So what’s the best solution? I think perhaps more than one road to Rome, but…..
I instigated some lovely chlorosis in my tank at 0.1ppm of Fe DTPA. It did not take long before my plants started to get pretty grumpy.
I tried an increase to 0.3ppm DTPA, and a combination of DTPA and EDDHA, also at 0.3ppm, without seeing improvement but a combination of DTPA and Fe gluconate (entirely unchelated) at 0.3ppm has done wonders.
This is counterintuitive, as Fe gluconate, being unchelated, is the least stable option and likely to remain available for only a short period. It is however super easy for the plants to uptake and likely to be preferably utilised.
So, plants get to suck up that Fe gluconate nice n quick and hey presto….happy plants!
Probably wouldn’t work if you were only dosing once pw of course, but on a 3xpw regime, it’s still doing ok for me.
I’d also have to say that I’m still testing, and my next plan is to remove the gluconate again to see if/how long it takes for chlorosis to show up (ie, is the experience repeatable) and perhaps to see whether an increase to DTPA only at 0.5ppm gives similar/better/worse results. I’d also be interested to test gluconate only and establish the minimum level the plants would be happy with.
I believe it’s possible that I may find that lower doses of the unchelated Fe gluconate could give better results than higher doses of the chelated products, despite it being a hard water tank…..but there’s a bit more work to do.
For yourself, it depends on what you want to achieve. I’m mixing my own Micro’s and Macro’s so have full control.
If, however, you want to carry on using your current micro mix as a base, it would be helpful first to understand whether the Fe in it is chelated to any level, and you could just try boosting this with some gluconate!!
Downside, it’s likely that pound for pound gluconate is gonna cost you more!!
You could also try adding some DTPA on top of your current base mix but I can’t tell you how much you’ll need before you see results. That would depend on just how little your plants are getting from the 0.5ppm of whatever Fe is already in the tank.
