I have had similar issues with some client tanks, others, no issues, I can lard it on.
What did I do? Tried a dozen different things. Few things worked.
I reduced the % water changes way down, that seemed to fix things.
I added some tolerant weeds that removed the salt in the tap water.
So slowly the salts reduced down via uptake by plants, and by limiting WC's, I was not adding a lot more salts.
So over a few weeks, the TDS dropped from 1300 to 500-700 range.
I can grow nice L "red", Gloss and Java fern, pennywort etc.
When I added ADA AS, I could grow a lot more species, but......only for so long, about 2-3 months, then the clay likely had been bound up by all the salts and no more active available sites left, so the TDS rose again.
I knew this was not due to ferts, this was something else.
I'd grow many species in the past with few issues, then suddenly, all sorts of issues.
I've not been able to keep shrimps very long in that tank either, something I cannot kill at home in any of my tanks.
Fish never get sick though, till I used the ADA AS curiously..............all that salt?
Growth has dependencies in that tank. Growth is slowed also. So less ferts are needed for growth.
Water changes seem pretty suspect for many of these issues for many folks also.
So simply stop doing them or reduce the % way down and keep some weedy species along with.
Some species did great till the ADA As ran out of binding the salts. Then they melted or died quick.
I'm going to add an RO and reservoir.
That's one management option.
If the fish load is high, this might not work so well, or if you muck the tank up often.
From the above example, you could suggest that the ADA AS offers some protection for awhile, but not long term.
Another client in LA also had ADA AS, but after awhile, it too started having issues growing other species due to the tap water.
Their solution was simple: remove the species of plants that did poorly.
ADA As makes a mess if you uproot and clarity issues can occur if mucky around often, so the client there switched to Eco incomplete.
Clarity went back up again, plant health was so so, so they started adding just the RO again. Plant health went back up.
If you use the RO, then you can see. You have some control. But that's not an option for a few folks here. I get that, I'm not keen on it for myself either. For high end clients, they get whatever they want.
Neither solution above zeros in on the exact cause, only what might be the suspects. From there, you need a reference tank to rule out the various hypothesis tanks. Those two customer tanks are NOT controls or reference tanks.
Now I do note that in both cases, RO fixed one and I suspect it'll do the same for the other once installed.
I cannot really say specifically what causes the issues, other than generally the tap water vs RO.
Maybe I do not care, I just want to grow anything in these client tanks? Yep.
I went after CO2, light management, Excel dosing, copper pipes and DI resin, ferts also.
Nothing worked. So the tap was all that was left.
Still, it narrows the options down much more as to the cause of these conditional intolerant plants or dependent factors.
Now you can go after those hypothesis. For larger client tanks, we install automated RO water changers.
A 16 ft tank recently started having issues in the midwest, easy plants etc, but the RO membrane had not been changed in liquid rock salty tap water. So the water quality went to hell.
Plants started dying, looking bad, algae etc. Water softeners, weird tap, salty tap, more RO maintenance routines, copper pipes, copper etc.
Clients have all sorts of issues. More than me.