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Grey/Black water tank question

November 26, 2014, 08:46:18 am

Last weekend I emptied my holding tanks for thje first time. I pulled the big handle and let it empty and then the smaller handle and emptied that. Do I need to add any water back into the tanks. or just start using everything again?  have another short trip planned this weekend.

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Re: Grey/Black water tank question

Reply #1 – November 26, 2014, 09:01:04 am

Good idea to add 5-10 gallons to the black tank. 

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Re: Grey/Black water tank question

Reply #2 – November 26, 2014, 09:03:49 am

Thank You!

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Re: Grey/Black water tank question

Reply #3 – November 26, 2014, 09:07:12 am

Everybody has their "secret formula" for taking care of holding tanks.  I have "heard" it is good to keep a little water in the black tank at all times - helps keep everything "mobile" and prevents accumulations that resist removal.  One tip I saw was to flush the toilet 10 times right after you empty the black tank.  For the grey tank, I don't think it is as critical, so we just let "normal use" take care of adding the required liquid.  We have also started using the Calgon/Dawn solution:

Calgon plus Dawn for holding tanks - success

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Re: Grey/Black water tank question

Reply #4 – November 26, 2014, 09:29:31 am

I don't use any of the "blue" chemicals in our tanks at all.  I use (esp in warmer weather) plain white vinegar in the black tank to neutralize odors. I use Dawn in the coach for dishes and lots of other cleaning, and it really does break down grease. I have done the Dawn & Calgon thing in the black tank from time to time ... and I think it works well. You really do not need a lot of fancy chemicals ... just some common sense.

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Re: Grey/Black water tank question

Reply #5 – November 26, 2014, 11:49:49 am

What in the world are you folks putting down the black tank that needs all that rinsing? We use Angel Soft tissue, pull the black then the gray and never add water. Never have any problems.

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Re: Grey/Black water tank question

Reply #6 – November 26, 2014, 02:54:06 pm

Since our grey tank fills faster than our black, I use the third valve method to add about 10 gallons or so of grey water back into the black tank after the third flushing (or until the effluent runs clean in the clear section of the dump hose). The flush procedure with a third valve has been described numerous times on the forum, but here is a summary;

Deploy the dump hose.
Open third valve.
open black tank valve.
When black tank is empty, open grey valve for a few seconds to let it run to flush the valves and hose.
Close the third valve while the grey is open (you can here the water from the grey tank rushing in).
When the inrush slows as the tanks start to equalize (or just watch the tank gage if you have one in the utility bay like I do), close the Grey valve.
Open the third valve (the black tank valve is still open).
Drain the black tank again, "rinse and repeat" until black tank runs clear
Close the third valve, open the grey and close the the black tank valve after letting 10 gallons or so grey water into it.
Open the third valve, let the grey tank drain fully.
Put the dump hose away.

Just what works for me... I may install a standard flush system that uses fresh water for long interval maintenance, but I don't like the idea of using so much fresh water to rinse the tanks. Most of the instructions I have looked at for them recommend filling almost full and repeating 2 or 3 times. It seems inherently wasteful. The third valve system wouldn't be effective without having the 3" pipe for the grey as well as the black (I have noticed that many so called high end SOB's use a 1.5" waste pipe for the grey). But it is very effective, and given the inrush of grey water into the tank, I am not concerned that some of the nasty stuff will find its way into the grey tank. Even if it did, knowing that many current high end coaches (including, if I am not mistaken, the IH45's) use a single large tank for both the wastewater and the sewage. I for one, am happy that the tanks are separate on our coach.
Don

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Re: Grey/Black water tank question

Reply #7 – November 27, 2014, 10:04:53 am

I'm with Larry. What are you guys doing - making holiday punch in those black tanks!
jor

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Re: Grey/Black water tank question

Reply #8 – November 27, 2014, 10:13:56 am

I found that even using the "correct" type of toilet paper that dissolves quickly we still would get false readings on the tank levels--especially the black tank. By doing the Calgon and Dawn treatment after every dump I finally got the 26 year old sensors to function correctly. Quite an accomplishment for sensors that probably hadn't worked for years. I even replaced the tank sprayer spinner and did not clean the bottom sensor.

Now I do the treatment after every dump just to keep the tank level system functioning correctly. It takes only one hangup on a sensor to screw up the sensor signal. Better safe than sorry.

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