I have been figuring out how to prevent chlorosis of those few plants in my garden which don't tolerate alkalinity well, such as Grevillea Robyn Gordon (which has survived the hot summer and the irrigation sprinklers and is flowering well) and Hibiscus syriacus, which is showing pale yellowish green leaves with green veins. No wonder, the soil and the tap water (pH 7,9) are both alkaline and saline in our region. I read, that it is very difficult to get the pH down permanently, but as all the other plants are doing fine, my concern is to get the pH down just for the grevillea and the hibiscus. I am not sure how to proceed at this time of the year. Could I use chelated iron as a foliar feed and add sulfur or ammonium sulfate in the soil? There are some phosphor-free fertilizers available, but that would be only in the spring, as they are rich in nitrogen.