presuming your ID is coorect ....

you will never trap them out of existence ... unless and until.. you solve the watering issue ...

i have lived thru this ONCE... key word there.. lol ..

how i solved the issue:

all the plants outdoors.. and applied an appropriate soil drench ... [i suppose this is where you will tell us you dont have a yard, rather you are in an apartment ...] .. and leave them out there for a week or two ...

in the mean time.. the house will clear of the gnats ...

and then learn how to water your plants ...

the alternative.. is to change out all your growing media ... by isolating all the plants in one room.. then working your way thru them.. until you can re-integrate them thru the house .. NEVER letting an infected plant out of the isolation chamber.. until its problem is solved ...

and then finally learning how to water.. to minimize or eradicate the problem... and you should be far ahead of me.. because i did not have the WW to learn...

there is no reason your media has to be this wet ...

i wish you luck.. they nearly drove me insane ... though that is a rather short drive.. most of the time.. lol

ken

Controlling Fungus Gnats can be difficult, but controlling the moisture level of the soil is simply the best method. When working the question desk at the local Cooperative Extension Service office while a Master Gardener most potted plant problems that came in were related to soils that were kept too wet for fear the plants would die of not. More plants die from root rot from too wet soils then die from too dry soils.
The link below provides some very good information about controlling Fungus Gnats.

Here is a link that might be useful: About Fungus Gnats

Thanks.
Are these fungas gnats?

You may want to question your potting medium, it could be too heavy and holding too much moisture, and there is also a chance you could be keeping it too moist. But if you have a heavy infestation, you're going to need some help other than changing cultural practices to get rid of them.

Get one of the BTi products and use it. Bacillus thuringiensis subspecies israelensis - nontoxic to mammals, birds, and fish, is specific to only mosquito larvae, and gnat larvae. Products may be Gnatrol, Knock out Gnats, others, and you can use mosquito dunks in a pinch if you don't find it in granular or liquid form. Drop a dunk in a container of water and let it sit over night, then use that water on your normal watering schedule, each time your water, for at least three weeks. It targets the larvae in the soil which must ingest it, and it takes a while to break the breeding cycle, but it does work so stay patient and consistent with the treatment.

There are pictures of Fungus Gnats on the web site I linked above.

Yeah I did look I just wanted to make sure.
Thanks again for the link :)

Thanks for all the helpful comments, they are driving me mad!

After advise I was given I decided to use a product called gnat off, its a larvicide but doesn't seem to be working, ive made lots of little traps using fly paper and put on the potting mix, ive caught thousands, on some traps theres more gnats than paper... anyway so I watered a palm and didnt bother emptying the saucer and that has the gnat off mixed in but there are still larvae swimming about in it and thats over a week guess it proves it doesnt work? I know I should of emptied the saucer but tbh doesnt make much difference.
Also my watering came in to question I think it was that I used bark to make 5-1-1 that wasnt sterilised.
Any body used gnat off?

Gnat off sold in this country is a repellent for humans and a very different product (for a different type gnat, a biting gnat) than you would find in the UK. The active ingredient in your same-name-product according to what I find online should be Bacillus Thuringiensis subspecies Israeliensis and it's effective for fungus gnats in containers, bird baths etc. It doesn't work instantly, isn't a contact insecticide, the larvae must injest/eat it. Are you using it as a soil drench, it must be poured into and allowed to run through the soil, not just added to a saucer at the bottom of the pot. If using it for containers indoors, I water by filling the pot to the brim over a sink, letting it drain, but then that's the way I water all houseplants that can be carried anyway, I never add little amounts of water to anything - it's flood, let drain.

The only reasons I can think of that would make it not effective would be skimping on the amount added to the water, solution not potent enough, or - it does have a shelf life and becomes ineffective if past its freshness date. The granular forms are good stored longer than the liquid, which do you have?

It does take patience to break the breeding cycle, my experience has been minimum of three weeks of consecutive use.

Yeah thats the 1Bacillus Thuringiensis subspecies Israeliensis :), I water in the normal way from above the container with a rose to get maximum drench, I make sure water runs out the drain holes as standard practice, ÃÂ I have the liquid version thats about 3 weeks old, I have a pipette so Im spot on with my dosage, maybe I need to give it more time perhaps.ÃÂ Im just not sure why the larvea were hoping about in the solution, fresh larvea maybe? I hope so.

I have found the Bti to be very effective against fungus gnats on the one occasion I had to use it. A terrarium I had planted became infested, and since you can't really let those dry out, I sprinkled a granular Bti product that I keep on hand for the bog garden next to my koi pond. The fungus gnats were gone within 24 hours.

Wow it sounds good, hope gnat off works if it doesnt ill look at getting bti

You have the BTi now, (Bacillus Thuringiensis subspecies Israeliensis), you just have it in the liquid rather than granular form in your Gnat Off UK. Any way you can introduce the bacterium into the soil will work the same - I've had the liquid product (different US company label of course) and like the ease of mixing, but like the granular product for longer shelf life.

I haven't had them indoors since one initial and frustrating experience a long time ago, but I raise quite a bit from seed and in this mild wet Z8 can commonly find them in seed flats outdoors.

Oh right, mine definatly doesnt work in 24 hours but I made extra effort today, I took all of my plants out side and literally submerged every container in a bucket with the solution and made sure all the mix was saturated, untill I see improvement they are not coming back inside lol, sick of gnats trying to go up my nose, they are the most annoying things ever.