Size the enclosure to the spider now
Choose the Psalmopoeus reduncus enclosure for the spider's current size, not the maximum adult measurement. The spider should be able to find prey, water and its retreat without being lost in unused space.
As a Costa Rican Orange Mouth grows, increase enclosure size in sensible stages instead of jumping straight from a sling tub to an adult display.
Lifestyle changes the shape
Because Psalmopoeus reduncus is arboreal, enclosure proportions should support that lifestyle. Floor space, height and substrate depth are not interchangeable.
The right dimensions for Costa Rican Orange Mouths are therefore about usable space, not simply litres or centimetres on a product label.
Fall distance and hard decor
For Psalmopoeus reduncus, keep fall risk in mind when deciding how much open height sits above the substrate. Heavy-bodied terrestrial spiders especially should not have a long drop onto hard decor.
Keep stones and heavy cork secure in the Costa Rican Orange Mouth enclosure and position them so normal digging cannot create a dangerous landing area.
When the enclosure is too small
Rehouse Psalmopoeus reduncus when the retreat no longer fits, required substrate depth is compromised or routine access to water and feeding has become awkward.
A Costa Rican Orange Mouth touching a wall is not, by itself, proof that the enclosure is too small. Look at how the whole setup functions.
Prepare the next size first
Set up the new Psalmopoeus reduncus enclosure completely before the move. Add substrate, retreat and water, then check ventilation and security.
Moving a Costa Rican Orange Mouth into a finished enclosure keeps the transfer short and avoids trying to adjust decor while the spider is exposed.