gnats breeding in bath grey water tank

[mtkbuckeye]

Gentrol is an IGR for insects and can be sprayed down drains for control of flies and their larvae. It leaves a residual insect growth regulator that only targets insects. It’s very effective.

[gw1800]

Not gnats. They are called sewer flies. Google them. The are actually beneficial in small numbers. We get these in our house drains once in a while.

They live on the organic matter in the sewer lines and lay their eggs there.

Keeping the drain line clean is the best way to get rid of them. Pouring hot, not boiling water down the drains once in a while helps clean the lines. So does baking soda and vinegar followed by hot water.

[Ps2hodges]

We had problems with gnats recently and this recipe took care of them. 1/2 cup warm water, 2 tbsp apple cider vinegar, 1 tbsp sugar and 6 drops of liquid dish detergent in a small cup that was set by the sink. The smell of the apple cider vinegar draws them to the water and the dish detr. Keeps them from flying.

[Puma26RLSS]

Originally Posted by pcsdpo

following the 2nd grade spelling thread . . . that should be "naughty gnats" . .. .

OK, How about the "knotty naughty gnat" problem? But to get back on topic, I did consult with my house and yard pest control tech. He endorsed the fill the tank with water/bleach combo. He suggested 2 gallons of bleach for the tanks 35 gallons of water. I did the suspected shower/bathroom sink gray tank first to see if that does the trick. If that doesn't work, I'll try not to go nuts over the knotty naughty gnats!

[Reverse_snowbird]

What you're really trying to get rid of is the fly larvae and eggs. Something as simple as dishwashing soap used daily over several days would coat the little buggers and keep the eggs from hatching. If that doesn't work, you might try Lysol cleaner. We've used that to get rid of all sorts of creatures from ants to spiders.
The key is daily treatment to kill the eggs.

[Puma26RLSS]

Sitrep on my "knotty naughty gnat" problem. Followed my pest guy's recommendation to fill tank with water and two gallons of bleach. Left it there for six days. Had about a dozen gnat carcasses lying around the bath this afternoon when I went back to check. Some progress especially for six days. Drained tank hoping that would wash some of the eggs and larva away. Will refill tank with vinegar and dish soap as recommended by forum and let sit for several days over Christmas.

[Grey Wolf 26RR]

I deal with this about once a year. The drain flies live in the biofilm located in your drain lines. Eliminate their food source and they go away. The best, easiest, safest way to eliminate the biofilm is this product:

https://www.domyown.com/invade-bio-drain-p-352.html

It is expensive but very effective if used according to directions.

[NJKris]

Originally Posted by Puma26RLSS

Sitrep on my "knotty naughty gnat" problem. Followed my pest guy's recommendation to fill tank with water and two gallons of bleach. Left it there for six days. Had about a dozen gnat carcasses lying around the bath this afternoon when I went back to check. Some progress especially for six days. Drained tank hoping that would wash some of the eggs and larva away. Will refill tank with vinegar and dish soap as recommended by forum and let sit for several days over Christmas.

You are going to have the cleanest tank in RV history. 2 gallons of bleach! Wow, that's how much I use to shock a 28,000 gallon swimming pool!

[Puma26RLSS]

Originally Posted by Grey Wolf 26RR

I deal with this about once a year. The drain flies live in the biofilm located in your drain lines. Eliminate their food source and they go away. The best, easiest, safest way to eliminate the biofilm is this product:

https://www.domyown.com/invade-bio-drain-p-352.html

It is expensive but very effective if used according to directions.

OK, I printed off the label of the product. Since I am trying to treat a 35-gallon holding tank, how much product do you think I should buy? How do you treat your tanks?

[dalford]

I guess I just don’t get how treating the tank will eliminate the gnats? They should not be able to get past the drain trap.

As the previous poster stated they live and lay their larvae in the scum built up in your drain on the high side of the trap. You need to kill the larvae and you do it by treating the drain pipe from the shower/sink down.

I use the stuff in the link below. It is a thick liquid that is poured (1cup) around the drain so when it goes down it costs the pipe and kills the larvae. Use as directed…

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

[Grey Wolf 26RR]

Originally Posted by Puma26RLSS

OK, I printed off the label of the product. Since I am trying to treat a 35-gallon holding tank, how much product do you think I should buy? How do you treat your tanks?

As Dalford said, you only need to treat from the drain opening to the water level in the trap. I do the kitchen sink, bathroom sink, and shower drain all at the same time. When you pout it in the drain do you best to get it to coat all side of the inside of the drain pipe. Hope that makes sense

[NJKris]

Originally Posted by Grey Wolf 26RR

As Dalford said, you only need to treat from the drain opening to the water level in the trap. I do the kitchen sink, bathroom sink, and shower drain all at the same time. When you pout it in the drain do you best to get it to coat all side of the inside of the drain pipe. Hope that makes sense

I thought we had these newfangled waterless traps in our RV's.

[dalford]

Originally Posted by NJKris

I thought we had these newfangled waterless traps in our RV's.

I do in shower, all others a J traps. .. does not matter about the trap, it is the scum that builds up on the side of the pipe before the trap that they breed in…knot kidding…lol..

[Puma26RLSS]

Originally Posted by dalford

I guess I just don’t get how treating the tank will eliminate the gnats? They should not be able to get past the drain trap.

As the previous poster stated they live and lay their larvae in the scum built up in your drain on the high side of the trap. You need to kill the larvae and you do it by treating the drain pipe from the shower/sink down.

I use the stuff in the link below. It is a thick liquid that is poured (1cup) around the drain so when it goes down it costs the pipe and kills the larvae. Use as directed…

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

OK, I ordered this stuff. Comes after Christmas. We'll see.

[MR.M]

Originally Posted by dalford

I guess I just don’t get how treating the tank will eliminate the gnats? They should not be able to get past the drain trap.

As the previous poster stated they live and lay their larvae in the scum built up in your drain on the high side of the trap. You need to kill the larvae and you do it by treating the drain pipe from the shower/sink down.

I use the stuff in the link below. It is a thick liquid that is poured (1cup) around the drain so when it goes down it costs the pipe and kills the larvae. Use as directed…

https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

They can get past the traps . mostly the larvae right before they hatch .

[dalford]

Originally Posted by MR.M

They can get past the traps . mostly the larvae right before they hatch .

Well, that thru a monkey wrench in my belief..lol. Anyway if they do get thru the trap they are going to get caught up in this goop…

[Librarianocnj]

I’ve been RVing for many years and just this year was taught by a fellow camper to make a water trap in your stinky slinky to avoid bugs and critters getting in from campsites dump connection.

Pic from rpod-owners.com

[Puma26RLSS]

Originally Posted by Puma26RLSS

OK, I ordered this stuff. Comes after Christmas. We'll see.

The first night I used this stuff---NADA! NO gnats or fruit flies at all. Outstanding! The directions say to use until you are satisfied with the results and then periodically as a preventative. I'll put in some each day for a week and report back. But I am very pleased this far.

[dalford]

Originally Posted by Puma26RLSS

The first night I used this stuff---NADA! NO gnats or fruit flies at all. Outstanding! The directions say to use until you are satisfied with the results and then periodically as a preventative. I'll put in some each day for a week and report back. But I am very pleased this far.

Great to hear! I think using it for a week is a good idea. I used it for several days and “was satisfied, no gnats” but then a couple of days later I saw a gnat. Used it again and no more gnats. I think it takes a while to eliminate all the larvae…..

[Puma26RLSS]

Originally Posted by dalford

Great to hear! I think using it for a week is a good idea. I used it for several days and “was satisfied, no gnats” but then a couple of days later I saw a gnat. Used it again and no more gnats. I think it takes a while to eliminate all the larvae…..

Well, I am four days into my "no more gnat" week. Daily gnat count is low, ranging from just one to four today. I coat each drain liberally with the goo---tub, sink, kitchen sinks, and even toilet. I put in sink plugs and keep toilet valve shut, of course. Got just under half gallon of the treatment left. Definitely making progress, but these little "buggers" are persistent.