Water dish
Keep a clean water dish available to Giant White Knees once the spider is large enough to use one safely. Place it where it can be removed and refilled without dismantling the main retreat.
If a Giant White Knee fills the dish with substrate or webbing, clean it and refill it. That behaviour is common and is not a reason to remove the dish permanently.
Substrate moisture
For Acanthoscurria geniculata, keep a water dish available and maintain a moderate moisture gradient. Avoid both bone-dry slings and persistently waterlogged substrate. Judge the substrate over several days instead of trying to keep every part equally wet.
Add water in controlled amounts for Giant White Knees. The lower layers can remain moist longer than the surface, especially in deep or fossorial setups.
Ventilation
Moisture without enough airflow can leave a Acanthoscurria geniculata enclosure stale and persistently wet. Cross-ventilation helps moisture move through the enclosure instead of collecting as constant condensation.
If a Giant White Knee enclosure smells sour, remains soaked or repeatedly grows mould across the surface, reduce water, improve airflow or both.
Slings and small enclosures
Small Giant White Knees enclosures dry faster because they contain less substrate and air volume. Check them more frequently without turning that into constant disturbance.
For a tiny Acanthoscurria geniculata sling, use a suitably shallow water source when practical and keep the substrate appropriate for the species and life stage.
Around moulting
Keep water available when Acanthoscurria geniculata is in premoult and after the moult. Do not disturb the spider to make it drink; simply make sure access is there.
After a Giant White Knee moults, leave the spider to harden. Hydration support means stable water access and suitable enclosure moisture, not spraying the animal directly.
Avoiding overwatering
More water is not automatically safer for Acanthoscurria geniculata. Persistently saturated substrate can create poor conditions even for species that appreciate a moisture reserve.
With Giant White Knees, aim for the moisture pattern the species needs while still allowing ventilation and some normal drying. The water dish remains the constant source while substrate moisture is adjusted as required.