I was looking at chelators to solve the calcium sulfate solubility problems for a more concentrated 1-part fertiliser. I’ve found that apparently some organic acids can complex calcium, specifically citric acid, but also others such as malic acid and lactic acid. I’ve already got malic acid that I could try. I would have to change the rest of the composition a bit – I’m specifically using ingredients such as urea phosphate to bring down the pH already. Also, I wonder if organic acids are a good idea for long term pH stability – I wonder if the acids breaking down in the plant’s water reservoir causes pH drift. Lots of things to test. Or I could just order an actual chelator like EDTA.
To be continued.