In my experience, the sciarid fly killer kit is completely effective against sciarid fly infestations - I can’t recommend the products and the company enough.
This is the 2nd time I’ve bought the sciarid killer kit from Andermatt Home & Garden (previously without the fertiliser).
When I first used the kit a few months ago, I had unknowingly repotted with an infested bag of soil, and flies quickly spread across all my houseplants. After using the kit, all the flies had died within a few days and no new flies emerged, meaning the larvae were eradicated too. I was so impressed and relieved - these flies are an absolute nuisance in the home and there were so many of them. Also, my plants were unaffected by the treatment (no damage or adverse effects). Instructions for using the nemotodes and sticky pads are easy to follow and both are straightforward to apply, and the advice on the website is very helpful for identifying and treating infestations.
Unfortunately, I recently purchased another bad batch of soil and the flies have gotten into various houseplants I’ve been cultivating for the past year. I bought this kit again without hesitation and it arrived the next day! I can’t speak yet for the fertiliser as it’s too early to tell; I’ll update the review if I can, but based on how great everything has been so far, I’m optimistic that it will be of help to my plants once the infestation is dealt with. 10/10, thank you Andermatt Garden!