Dave thanks for answering.

I have dwarf citrus growing in containers; see my
http://www.rossde.com/garden/dwarf_citrus.html. I use a potting
mix that tends to be acidic because of the large amount of peat
moss; see my
http://www.rossde.com/garden/garden_potting_mix.html. The mix
also contains bone meal and gypsum, both of which are sources of
calcium.

Since the mix drains well, nutrients leach away. This is
accelerated by the fact that the containers are slightly elevated
on loose bricks and do not sit in any saucers or non-draining outer
containers. Thus, I have to feed frequently (but lightly to avoid
burning confined roots). I alternate between a commercial citrus
food and ammonium sulfate. Because citrus is sensitive to a lack
of zinc, I also give small doses of zinc sulfate. All of these are
acidic.


Even mine are elevated on bricks, used to be fine with their soil, renewed
every two years, using a specific mixture of meso and micro elements
designed specifically for citrus.
Probably this year I've exceeded a little bit fertilizers and this may have
altered proper absorption ef elements.

http://www.angelfire.com/blog/herman...esio/index.htm

Have a look at those pics of the lemons of mine, about magnesium
deficiencies I've posted lately.

Nevertheless the water is very bad in term of calcium carbonate, high Ph
(8/8.5).

Still wondering for the future if soluble calcium ions can be more dangerous
for the lemons instead of the calcium carbonate...

Thanks for answering again and wishing to continue this freindly
conversation.

Regards