Common issues

Mold and fungus.

Organic matter and moisture is going to mean micro fauna and bioactivity, not all mold is bad, some is actually a great sign that your tank or tub is doing well. Here's a few common types of mold or growths that you may see. A general rule on getting rid of mold and fungi is to decrease moisture and humidity, and allow springtails to do their job. If fruits or vegetables you placed in the tank are starting to mold, simply remove from the tank, springtails will likely eat any food mold that is left behind.

White, fluffy or stringy mold: This is most common with new tank set ups or when new materials are added, and it's nothing to worry about. Think of it like a fish aquarium building its initial bacteria balance, it's good for long term micro activity. While unsightly, it won't hurt your isopods, and they may graze on it. If it's spreading too aggressively or you just think it's gross and prefer to get rid of it, you can increase air flow and decrease the humidity for a while. Springtails will make short work of this mold bloom, if it's a new tank it may take a week or two for your springtails to establish themselves and begin cleaning it up.

Mushrooms: These can come in various shapes and sizes, and their cause is often as simple as something added to the tank had mycelium living on it. It is very unlikely you have a dangerous mushroom growth. Very common types are long stemmed white or brown ones growing out of wood, or white, web-like mycelium spreading through substrate. Isopods will happily feast on these mushrooms, and springtails will munch on the source mycelium. If growth is overwhelming your tank, you can allow it to dry out a bit and remove what you can see manually.

Green or yellow slime: Slime molds can appear if your substrate is simply too wet. This is also not harmful to your critters, but many report that their clean up crews will avoid eating it, even when in its dry state.  Manual removal may be required. It's a good idea to get some more ventilation in your enclosure and allow it to dry out if your substrate can facilitate slime molds, they like things really wet.