How high to fill biocube

[Qasimja]

This 29g biocube is almost ready to start running but I'm not sure how high to fill it the back chambers are mostly full and this is where the DT is should I continue to fill it?

 

[Saltyreef]

Go ahead and turn it on.
The pump will displace water from the back to the main display. If it starts sucking air, you know you need more water in the back.
You should have a water level line in back too though i always filled it higher than that due to not using media baskets.

 

[Qasimja]

Go ahead and turn it on.
The pump will displace water from the back to the main display. If it starts sucking air, you know you need more water in the back.
You should have a water level line in back too.

yea there is

 

[Saltyreef]

yea there is

Just fill it to the max water level line when its running then