bugs in the black water tank

old guy wrote:
only thing I can see in the catalog that is blue and about $30 a gallon is "pure power"

That looks like the stuff. They told me to clean the tank with the wand, add 8 oz, fill to 1/4 tank and take the RV for a rough ride to let the chemical splash around. I did. The amount of bugs significantly decreased and disappeared over several cleanings and applications. We are 100 percent sewer fly free. I continue to add 2 oz after each black tank dump. Occasionally, I add a little to each drain.

We also found them coming from our drains, so dump a couple oz down each drain including the bath tub at the same time you do the black tank.

Do a Google search for "drain flys". Resilient little critters. It only takes a couple hours after they hatch for them to lay more eggs.

I got distracted and left the black valve open for a week or so at our winter campsite. It won't happen again.

Paul

I had wasps float out when I cleaned and drained my tanks this summer. Turned out I had a wasp nest in the vent pipe, the suction created when opening the dump valve sucked wasps into the waste tank. I placed a screen on the top of my vent and didn't have any more issues all summer.

popeyemth wrote:
Anything that deadly would be bad for the septic systems you dump into
They will die a natural death if you flush the tank good and leave it dry for awhile
To prevent a reinfestation leave a dip in part of your sewer hose when connected to make a water seal between you and the dump/sewer
Good Luck, Mike

This is the exact reason I NEVER leave any of my tanks open. Also. Leaving the black tank open WILL cause a very unwanted repair bill. When you have to have the big PILE removed. NEVER EVER leave the black tank open.

only thing I can see in the catalog that is blue and about $30 a gallon is "pure power"

I had the sewer flies for a year. As you did, I posted here and tried all the suggestions. None of them worked.

I went to Majors RV in Bourne, MA. I was told to clean the tank with a toilet wand and to use a tank deodorant/cleaner they recommended. It worked.

Unfortunately, I am 1,600 miles away from our RV, and can't remember the name of the product they recommended. It came in different size containers from small to a gallon and was very blue. The gallon was about $32 at the time. I continue to use the product.

Majors RV Repair has a "stump our tech" section. Send them an email and ask what it is.

I hope this helps.

I bet a few tablespoons of household ammonia left to fume the tank for an hour would be effective.

Leave both grey and black tank valves closed until you need to dump. The flies are coming out of the sewer up the hose to the rv

Flush quicker, Don't stand there holding down the foot valve. Spray when the they get out but I would not put anything in the tank. Good Luck

Just spray some bug killer down toilet with water off.then close toilet blade and let sit. Then flush

Also spray some down vent lines from roof.

Don't leave black tank drain open so the bugs can't get in plus other problems with leaving it open (poop pyramid)

The loop in sewer hose is OK BUT why leave ANY drain valves open so bug can get from sewer system back up into your grey tank.

Sewer flies are common in sewer/septic systems even treatment plants.....don't invite them in. Leave drain valves closed until dump time. They fly but aren't very good swimmers especially upstream.

Sounds to me like you need to give the tank a good flush, and then flush better at every dumping. As far as killing and removing eggs, I would think water would do the trick.
Do you add water to the tank after you dump between trips? I have found that by adding 5 gals or so water in tank versus sitting dry between trips help keep odors and bacteria from forming. Steve