Comparing timeseries with linkaxes but axes won't link anymore.

I have several timeseries that I am trying to compare. I want be able to zoom in to periods of 2-3 days at a time to step through the data and compare trends in different parameters. I was using linkaxes to do this and for a while it was working. For some reason it is no longer working! Any ideas where I might be messing it up? I copied some code below and I am attaching a screen shot of the (disgusting) full timeseries...

%% Stack all timeseries for mooring

start = 'Aug-10-2018'

stop = 'Oct-5-2018'

plotnum=9

f2=figure(2)

%____________PH________________

ax(1)= subplot(plotnum,1,1)

n = size(pHint,1);

colors = flipud(jet(n)); %flip color scheme

h = plot(X,pHint);

set(h, {'color'}, num2cell(colors, 2));

legend('SP2 6.12 mab','MF4 5.18 mab','MF7 4.52 mab','MF3 3.56 mab','MF2 2.58 mab','MF5 1.45 mab','SP1 1.06 mab','location','best');

ylabel('pH');

title('PK Mooring')

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks')

%xlim([datenum('July-18-2018 9:00') datenum('July-20-2018 00:00')]);

%___________OXYGEN________________

ax(2)=subplot(plotnum,1,2)

plot(pk100m_time,do_pk100m,'Color',[0 .4 .4]);

hold on

plot(pk5_time,do_pk5,'Color',[0 .8 0]);

plot(pk3_time,do_pk3,'Color',[.6 .6 1]);

plot(pk1_time,do_pk1,'Color',[.4 0 .6]);

ylabel('DO (\mumol/kg)')

% ylim([2.5 14.75])

% set(gca,'fontsize',16);

legend('Kelp Surface','PK 5 mab','PK 3 mab','PK 1 mab','location','best')

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks')

%__________TEMPERATURE______________

ax(3)=subplot(plotnum,1,3)

n = size(TC,1);

colors = flipud(jet(n)); %flip color scheme

h = plot(X,TC);

set(h, {'color'}, num2cell(colors, 2));

legend('SP2 6.12 mab','MF4 5.18 mab','MF7 4.52 mab','MF3 3.56 mab','MF2 2.58 mab','MF5 1.45 mab','SP1 1.06 mab','location','best');

ylabel('Temperature');

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks')

%_________Depth (pressure)________________

ax(4)=subplot(plotnum,1,4)

plot(ADCPtime, PK_depth)

ylabel('Depth (m)')

ylim([7.5 11])

x = datenum(start):7:datenum(stop);

set(gca, 'XTick', x);

datetick('x','mm/dd','keepticks');

%_________Cross-shore current________________

ax(5)=subplot(plotnum,1,5)

plot(ADCPtime, PK_cross)

ylabel('Cross (m/s)')

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks')

%_________Alongshore current________________

ax(6)=subplot(plotnum,1,6)

plot(ADCPtime, PK_along)

ylabel('Along (m/s)')

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks');

%_________BEUTI__________________

ax(7)=subplot(plotnum,1,7)

plot(btimestamp,Bmean3637,'.')

ylabel('BEUTI')

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks')

%__________Fluorescence_____________

ax(8)=subplot(plotnum,1,8)

plot(ftime,fluo,'Color',[0 .8 .8]);

ylabel('Fluorescence');

% set(gca,'fontsize',16);

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks')

%_________Wind__________________

ax(9)=subplot(plotnum,1,9)

%Plot 2 principal components

plot(wtime,pE,'k')

hold on

plot(wtime,pN,'b')

h=legend(['Dir = ',num2str(90-theta,3),'^{\circ}'],['Dir = ',num2str(-theta,2),'^{\circ}'],...

'Location','best')

ylim([-6 8])

ylabel('Wind speed (m/s)')

x = datenum(start):7:datenum(stop);

xx = datenum(start):1:datenum(stop);

set(gca,'XTick', x);

ax=gca;

ax.XAxis.MinorTick = 'on'

ax.XAxis.MinorTickValues = xx

datetick('x','mm/dd','keepticks')

linkaxes(ax,'x')