Hi all BeardedKiwi here.
Mumbo Jumbo in his latest Hermit Craft Episode 100.5 had an issue with removing the corner blocks from his water wall surrounding his Guardian Farm.
Here is my solution to get rid of those glass Pillars.
Step 1: Setup
To get started you will need to place a pillar of sand in the inside as shown, and also a pillar of glass or other (non- gravity affected) block to make a square.
Step 2: Remove Side Blocks
Next is to remove the Existing Glass pillars that made up the corner of the Wall
Step 3: Remove Sand and Final Glass Pillar
now Remove the sand in the inside.
Then remove all but the top glass block that you placed in step 1.
Step 4: Remove the Final Glass Block
now as a precaution i built two sand pillars to catch any water that may fall out.
next remove the last glass block and no water should flow in.
Step 5: Done
Now you have a wall of water free from Glass or other border Blocks
the trick is to prevent water source blocks from forming in the corner
Hope this helps you Mumbo.
A shout out in your next video would be cool.