Installing overflow rain barrel #2

I installed the first of my overflow rain barrels the other day.  I placed overflow barrel #2 behind the trellis in the corner of my yard.  This will help to keep it out of site.

This barrel will be fed by the rain barrel that came with my house.  When this barrel gets full it'll overflow and fill the new barrel.

You'll notice that this barrel has two overflows.  I thought that the original one was too low.  So I added a second one that was higher.  I used the lower one to connect to the new barrel.  Since I'm using 1/2" tubing it's quite possible that the barrel could still overflow during heavy rain storms.  The second overflow should alleviate this issue.

The tubing attached to the valve at the bottom of the barrel is plumbed to the other barrels in my back yard.

This picture shows the distance between the two barrels.

I didn't measure, but the overflow barrel should be lower than the came-with-the-house-barrel.  I didn't put it up on blocks, and visually it looks lower.  This is the reason why I'm filling that barrel from the overflow instead of from the hose bib (like I did with the other barrels).  Water will seek its one level and I want to store as much of it as I can.  I don't want all of my barrels to drain down to the lowest overflow on the lowest barrel.  I could install a float valve, but for this instance that would make things more complicated than they need to be.  Besides, I always have the option of moving water between the two barrels by moving the fitting connected to the overflow to the hose bib.

Now I just need it to rain again...