The larvae you see are likely from mosquito eggs, not produced by the pet fountain. During summer, there are more flies and mosquitoes, and these insects typically prefer to lay eggs in damp areas.
Here are some suggested measures:
1. Check if the pet fountain is too close to the litter box or other areas that attract mosquitoes, and consider moving it further away;
2. The current filter is no longer usable, as mosquito eggs have been washed into it;
3. It is advisable to connect the power and activate the continuous mode, this can effectively prevent mosquitoes from landing and laying eggs. Alternatively, you can look online for devices that repel mosquitoes and flies, which can also help;
4. It is recommended to change the water every 2-3 days and clean the device.