Re: puzzling, persistent substrate dampness
My first thought is wicking. It almost has to be something wicking.
Wicking can actually move a lot of water, faster than you might think. It moves so much water, it has inspired an entire method of pump free hydroponic farming.
I used the Growstone-like medium as a drainage layer
More details on this please. Is that the white stuff at the front, bottom, of the viv? If so, and if I'm seeing this right, I believe that's your culprit. I see small white particles touching the bottom of the vivarium, and touching the ABG. To my eye, those particles look way to small to be an effective drainage layer. Large particles, like pepples, are big enough that the surface tension of the water breaks before real wicking can really develop. The smaller the particle, the smaller the space between particles. That means the surface tension of the water can easily jump from particle to particle, lifting water ever upwards into the ABG mix. Now, you said growstone like media. To me that means something like LECA or Hydroton. That means porous. Porous holds more water than the pebbles we discussed. The fact that it's holding more water, helps keep everything wet, and further enhances the wicking action.
I believe you did something I did once upon a time. In using too fine a material for part or all of your drainage layer, I created a very efficient, completely power free, hydroponics system! I made the reverse of what I wanted to do. I did it using Turface, or calcined clay, which I've come to believe is a very poor choice for a drainage layer. I found that only a one inch strip of turface, used to hide the eggcrate/screen drainage layer, pulled several gallons of water out of the bottom and up into the substrate. It emptied the false bottom overnight.
If my assumptions are correct, I'm pretty sure it's all about that drainage layer being too fine a particle, and possibly porosity adding to the problem.
Doug aka Pumilo
The second "i" is silent. It's so silent it's not even there!
Last edited by Pumilo; 06-29-2020 at 03:55 AM.