I planted some sweet potato tubers that have been growing vines for a few months now. The plant is potted in the same cactus soil I use for my cactus plant-- very high drainage-- in a tin pot with a dozen drainage holes on the bottom. I water it with about half a cup of water + plant food per week. I feel that this is not too much, but please let me know if it is.
I recently got an infestation of fungus gnats. I didn't realise what it was at first, so unfortunately I didn't start treating until there were about 50-60 (based on the number of adults I've killed with sticky tape/ a makeshift sticky swatter). In summary, I'm catching the adults, I've mixed up the top inch of soil with about a quarter cup of cinnamon, and daily I spray the top of the soil with 3% hydrogen peroxide solution.
Are there any other preventatives measures I can take? I had fungus in the pot about a month ago, which I'm sure lead to this situation, but I water so infrequently I'm not sure what to do about that. Should I start watering it with a <3% hydrogen peroxide solution as opposed to regular filtered water? Not sure if long term that would harm the plant. Also please note that my cactus doesn't have gnats, so I don't think it's a soil quality issue.