Test Tube ant Farm v2

Here are photos of a test tube ant-farm I use instead of concrete or plaster artificial nest.
It is used since last year, so it is viable.
It is an evolution of the v1 : I've used threaded rods instead of a wood frame, and test tubes enter a hole instead of surrounding a washer.
the aim is to get a low maintenance ant-farm, test tubes providing moisture for months. test tubes can be removed provinding access to brood if needed. Designed for 20ml test tubes (16,3mm x 150mm).
I'm still thinking about a look-a-like thing, I think a V3 will be a mashup of V1 and V2.
And maybe V4 will be a pintable setting.