[kevinpereira79]

So I'm planning on dirting my tank today. I've read the Miracle Gro organic potting mix (which is what I got, but it's called gardener's choice or something like that, under the Miracle gro brand), comes with gnats. I'm an insectophobe and very paranoid. If I just put the dirt in my tank and straight up flood it with the water, how likely am I to get gnats?

 

[Pierre Monteux]

I've never done soil in an aquarium before, however, if you're looking to make sure the gnats are completely dead, there is this.

Bake Soil to Pasteurize Before Germinating Seeds

And now I'm wondering if that is where the gnats in my houseplants came from.

 

[kevmo911]

So I'm planning on dirting my tank today. I've read the Miracle Gro organic potting mix (which is what I got, but it's called gardener's choice or something like that, under the Miracle gro brand), comes with gnats. I'm an insectophobe and very paranoid. If I just put the dirt in my tank and straight up flood it with the water, how likely am I to get gnats?

They should drown, no worries.

And now I'm wondering if that is where the gnats in my houseplants came from.

Yep. Or, if they've ever spent time outside, they could have come in that way. Yellow sticky tape works, or petroleum jelly on anything yellow, like those free paint sample papers or a shiny bright yellow school folder. Also, you can buy beneficial nematodes for a long-term solution. Gets rid of eggs.

 

[JJ09]

Yes, that soil often has gnats. I use it with my houseplants and frequently have fungus gnats hatching out in summer. It's really annoying. I don't want to bake my soil- makes the house stink. I don't know if this is useful in aquarium situation, but I discovered that putting bounce dryer sheets near the plants keeps the gnats away (also stick them in my hat brim when gardening outside now, keeps midges off my face!)

I doubt gnats would hatch out underwater, though. Won't they drown?

I smack any gnats or fruit flies I find in the house and put them in my tank on purpose- the fish love a fresh snack!

 

[Ccatanthony]

Been doing pest control for the better part of a decade, fungus gnats(which are the typical gnats found in potting soil) will not survive when you fill the tank. As far as the comment above about house plants, covering the soil with an inch of common silica sand will generally fix the problem along with reducing watering.