mushrooms wont open

[jnllargo]

purchased small rock w/ 7 green mushrooms 3 weeks ago
in store you could not see rock
at home they have not opened
other tank shrooms are thriving striped, brown, blues
90 gal
temp.78-80
cal 440
ph 8.1
alk 14.6
nitrate 0
nitrite 0
amo 0
4x65w pc light
i have tried different depths and flow
1 popped off rock last week
what 2 do ?

 

[LegendLand]

alk is too high, lower it to around 10..you may have too much flow on them as well..common problem with mushrooms