AusBonsai

63pmp in a previous post stated
" Excess ammonium does cause toxicity in plants, however organic forms of N such as proteins, and nitrate, does not. So a dilute organic fert like fish emulsion would be good. (Zeolite hordes ammonium which can be released at inapproprite times, or gets converted to nitrate, which has an impact on some plants, like J maple)"

I had an Hinoki Cypress which was doing magnificently, until I repotted it into this "new fantastic potting mix, containing zeolite (amongst other ingredients), then gradually the tree seemed to deteriorate. Couldn't work out what was happening, and on reading the above information, could it have been the Zeolite. Could it have altered the pH of the mix I used? Any thoughts on Zeolite would be appreciated.

I had a Hinoki that deteriorated as well, that was potted in pine and diatomite. Tree just did not recover, my case could have been too much water and stress when repotted.

Purchased another, repotted as tree was pushing new growth. Did not work on tree outside of pruning excess growth. This tree is in primarily in bark and pumice with zeolite added. Tree is growing strongly.

Don't have all the science to support, but don't see zeolite being the cause. Happy to be corrected.

When did you repot the tree Hawkeyes?

Anecdotally I have been growing a Hinoki with Zeolite since late 2012 with no problems.

Whilst I understand that your tree "grew well" for 5 years I'm still not convinced that it will indefinitely tolerate your warmer climate and lack of dormancy.
I too find it both admirable and peculiar that you don't just move on and persist on your quest for answers to your poor Hinoki!

FWIW.
I've been growing various species of tree's for quite some time - some thrive others just don't??
Whilst I try to find out reasons for and tailor treatment for the ones that misbehave, watering, fertilising, locations etc.
Sometimes it's just best to leave a species and focus on those that work best for you.

In summary I don't believe horticulture to be an exact science and often reasons for failure or other are generally little more than guesses.
Clearly there are exceptions to this but that's the way I see it...

="hawkeyes"]
" Excess ammonium does cause toxicity in plants, however organic forms of N such as proteins, and nitrate, does not. So a dilute organic fert like fish emulsion would be good. (Zeolite hordes ammonium which can be released at inapproprite times, or gets converted to nitrate, which has an impact on some plants, like J maple)"

No. zeolite protects plants from ammonium toxicity. It does attract ammonium but does not ''release it at inappropriate times''. It holds it until the plants use it. Organic nitrogen gets converted to ammonium in the medium.

I had an Hinoki Cypress which was doing magnificently, until I repotted it into this "new fantastic potting mix, containing zeolite (amongst other ingredients), then gradually the tree seemed to deteriorate. Couldn't work out what was happening, and on reading the above information, could it have been the Zeolite. Could it have altered the pH of the mix I used? Any thoughts on Zeolite would be appreciated.

No not the zeolite.