gray tank flush

[dragonfly]

We would like to know how to flush the gray tanks, and how often?

We have found out how to flush the black tanks. 

 

Thanks for your help, Dragonfly travelers.

[Kirk W]

If you don’t have a tank flush system you could fill it with water and empty it but I have never done that with my gray tank in 40 years of RVing. Once each year I do mix a 5 gallon bucket with TSP and put it into the tank just before traveling and then empty it upon arrival. 

[Twotoes]

You dump when it's full, for most people just after your weekend trip, or if a full timer like me about once a week. I always flush my gray everything dump and flush my black so that the soapy gray water rinses the hose. 

[VC 23RSS]

I currently have mine filled with a cup of Dawn and water.  It will simmer for a total of three weeks before dumping it the morning I leave.  Then fill with a 2-3 gallon of water and a couple oz of Dawn.   Drive a day and dump the following morning.  Hopefully this will clean the tank.  I don't use bleach.

[2gypsies]

We've never flushed the gray tank.  A helpful hint is to never let garbage, coffee grounds or grease enter the tank.  We always took a used paper towel or napkin after eating & wiped the plates, fry pans, pots off to remove the majority of stuff.

[Star Dreamer]

When I installed my Tornado tank flush on my black tank, I put on one my grey tank too so I flush the grey tank whenever I am doing the black tank if I am at a full hook up site unless I am running short of time or I am doing it at a public dump station and have others behind me. It does not need to be done very often but it can't hurt it either. 

[RV_]

Dishwashing liquid and some water just before we move and let it suds up in there. Then dump it on arrival. Or in place and fill and flush.

[GlennWest]

We have a washing machine and a dishwasher so it get plenty of water 

[sandsys]

8 hours ago, VC 23RSS said:

I currently have mine filled with a cup of Dawn and water.  It will simmer for a total of three weeks before dumping it the morning I leave.  Then fill with a 2-3 gallon of water and a couple oz of Dawn.   Drive a day and dump the following morning.  Hopefully this will clean the tank.  I don't use bleach.

That needs to blue Dawn. You don't want the antibacterial stuff going into a septic system. Blue Dawn cuts grease even in cold water. But, I always figured just dumping my dishwater and shower water down there provided enough soap to not need to add to it.

Linda

Edited September 16, 2022 by sandsys

[TXiceman]

Bacteria is not an issue in a black tank, as it is not a septic system.  You dump the tank every week or two.  Just use lots of water and septic safe toilet paper.  If you want, you can use a non-toxic tank chemical.

Ken

[Jinx & Wayne]

19 hours ago, RV_ said:

Dishwashing liquid and some water just before we move and let it suds up in there. Then dump it on arrival. Or in place and fill and flush.

We do this about every six months just after a long stay (we are full time). I also add a cup of borax dissolved in a couple of gallons of water. I put a total of about five gallons in the tank to slosh around.

Wayne & Jinx

[sandsys]

3 hours ago, Jinx & Wayne said:

We do this about every six months just after a long stay (we are full time). I also add a cup of borax dissolved in a couple of gallons of water. I put a total of about five gallons in the tank to slosh around.

Wayne & Jinx

To put this in perspective, how big is your gray water tank? Maybe the reason I think dishwashing and shower soap was enough is that my gray water tank was only 20 gallons?

Linda

[bruce t]

I'm with RV. We never dump before hitting the road. Some dish washing liquid into both black and grey tanks. Then when we get to our campsite we dump the black followed by the grey. Then a quick rinse with water and no smells while camping. The road movement stirs up and cleans the tanks.

 

 

[Ray,IN]

I do nothing special, with the exception of avoiding dumping frying grease and food into the gray tank. Haven't had a  problem with a gray tank in the past 40  years.

[rickeieio]

1 hour ago, Ray,IN said:

I do nothing special, with the exception of avoiding dumping frying grease and food into the gray tank. Haven't had a  problem with a gray tank in the past 40  years.

X2.  The gray tank has plenty of soap already.

[2gypsies]

Dishwashing liquid leaves a scum and it's not good for the sensors.  Try doing dishes in your sink and drain the water without rinsing the sink.  What's left?

You don't need to add more soap to the tank. There's plenty in there already if you think soap is good.

[rpsinc]

I seem to remember that the culprit is glycerine or animal fats(grease).  It sticks to the surfaces and by default the sensors.  Seems I read some using Calgon to clean their tanks.  Safe and effective.  Also use some ice cubes before traveling to act as a scrubber while on the road.  Not used personally mostly because I am a fan of the idea of using blue Dawn, but dont do the dumping AFTER travel.  Will definetely do that next time to see if that is better.  Should be from where I sit.

Great thread!

[Kirk W]

13 hours ago, rpsinc said:

Seems I read some using Calgon to clean their tanks.  Safe and effective. 

That is one of the interesting parts of RVing mythology. Calgon is a product that causes minerals in hard water to solidify and settel to the bottom as particulate matter. Read the lable on their box sometime. It has nothing at all to do with grease. (My mother used it for laundry water from the well for yerars.)

The following is a quote from the Calgon Co. website. Calgon has a unique formulation with active ingredients being polycarboxylates which softens hard water, preventing limescale from forming. The addition of Calgon to hard water causes the calcium and magnesium ions of hard water to displace sodium ions from the anion of Calgon. This results in the removal of calcium and magnesium ions from hard water in the form of a complex with Calgon.

[JimK]

I have a cassette toilet and I use chemicals to keep the odors in check.  I found that after a few weeks of use the grey water tank really stinks.  I now use a screen on the kitchen drain to remove almost all the food particles.  That helps but the odor still builds over time.  Periodically I add a half cup of bleach to the tank and then rinse it a couple of times when I have access to a dump station.

Many NFS or NP campgrounds do not have dumps and of course dumps are extremely rare for BLM and bookdocking areas.  My grey water tank is small.  I have a 5 gallon bucket that I can use for a couple of trips to a suitable place to dump.  That might be an area designated for tent campers to dump kitchen water, a toilet or some other suitable place.  This works a lot better when dumping grey water that is mostly just shower water instead of grey water that really stinks.  Again, a little bleach and rinsing the tank every few weeks works wonders. 

[dragonfly]

Great answers. Very helpful. We hadn't thought about how we were already adding soap from dishwashing and the shower.

Another question: I think the answer might be No, but can the gray tank handle our black tank treatment liquid that cuts odor, dissolves toilet paper and reduces other things to liquid? Or is it too caustic for a gray tank?

 

Dragonfly

[Kirk W]

11 minutes ago, dragonfly said:

can the gray tank handle our black tank treatment liquid

In most cases the answer is yes. Look at the directions on the lable as most products say that they are for both tanks but there are a few companies that make a product for each tank. You should never use any caustic product in your waste tanks because that would damage the septic systems used in many campgrounds but any commercial product isn't likely to be that way. The second thing I would suggest is that most of us who have been RVing for years do not usually use any kind of wate tank chemicals. As long as you use enough water when you flush, the natural bacteria in the black tank will liquify what is there as long ast it is only human waste and septic safe toilet paper. I have not used any sort of tank chemicals in more than 20 years, except that if we have company and are filling the black tank more quickly than normal, only then do we use one of the biological additives just to speed the process. In most cases the same natural process that makes a septic tank work starts in the black tank and over a few days will liquify most of what is there such that the rush when emptying a half full or more tank will carry out any remaining solids. 

[Ray,IN]

soap is made with oils/fat and lye. I'm sure all older military veterans remember the tan color blocks of issue lye soap.

[sandsys]

1 hour ago, Ray,IN said:

soap is made with oils/fat and lye. I'm sure all older military veterans remember the tan color blocks of issue lye soap.

Examples of fats and oils used in soap-making include:

• lard
• tallow
• olive oil
• coconut oil
• avocado oil
• almond oil
• jojoba oil
• hemp oil
• cocoa butter
• mango butter
• shea butter

Use oils from animal or vegetable sources only. Soap can’t be made with petroleum-based oils.

[2gypsies]

4 hours ago, JimK said:

I have a cassette toilet and I use chemicals to keep the odors in check.  I found that after a few weeks of use the grey water tank really stinks.  I now use a screen on the kitchen drain to remove almost all the food particles.  That helps but the odor still builds over time.  Periodically I add a half cup of bleach to the tank and then rinse it a couple of times when I have access to a dump station.

Many NFS or NP campgrounds do not have dumps and of course dumps are extremely rare for BLM and bookdocking areas.  My grey water tank is small.  I have a 5 gallon bucket that I can use for a couple of trips to a suitable place to dump.  That might be an area designated for tent campers to dump kitchen water, a toilet or some other suitable place.  This works a lot better when dumping grey water that is mostly just shower water instead of grey water that really stinks.  Again, a little bleach and rinsing the tank every few weeks works wonders. 

Your occasional use of bleach would be OK for a home septic but at a campground that has a septic (which most public campgrounds have), if many campers use bleach it definitely is not good for a septic.

"Bleach is used all over your household. But, your septic system does not approve. Limit the number of bleach products you use, how often you use them, and eliminate any highly concentrated products from your cleaning routine."

https://advancedsepticservicesfl.com/chlorine-bleach-septic-systems/

[Kirk W]

Most popular “soaps” on the market—both bar and liquid—are made from synthetic ingredients, so they don't actually meet the definition of soap. For example, here is an ingredient list from a popular brand of shower gel:

Water, Sodium Laureth Sulfate, Sodium Sulfate, Cocamidopropyl Betaine, Fragrance, Sodium Lauroamphoacetate, Citric Acid, Sodium Benzoate, Polyquaternium-10, Disodium EDTA, Methylchloroisothiazolinone, Methylisothiazolinone, Green 3, Green 5, Red 33.