Assuming an ID grow; hoping to understand your problem yet not willing to download your link, but I will guess by giving you my two cents. I have identified HM as slightly brown in color. They are beneficials and typically live (top layer of soil) near their food source i.e. fungus gnats, etc. I have not experienced any adverse effects to my plants with these critters. If they came with your soil, that's a bonus!
Aphids on the other hand, adversely affect the plant resulting in fatigue, discoloration, stunting, etc. In other words, the plant shows that it is ill. Typically whitish in color and a little bit larger, root aphids can be hard to get rid of. Some treat with neem or pyrethrum products. IME, it is best to get rid of the plant entirely and if an ID grow to implement decontamination procedures within the grow space. These infestations can get out of hand quickly given the right environment!
Some things to look for: wet soil due to over-watering, lack of ventilation, excessive temperatures and humidity. Other insects that might carry them into your environment.
Suggestions: keep your soil dry, ventilate and keep temps moderate and in a narrow range. Do the same with your humidity. Use a product like Tanglefoot to deter bugs from climbing up and down your main stem. Cleanliness is Godliness.
If your soil is store bought and you can verify that it was the vector, take it back for a refund. Let them know that you "have pictures". If no go, do not continue doing business with that company. Hope I got it right and that this helps.
Mu