mikerodg Report post Posted September 27, 2015 We are frequently at an RV park for a week at a time. I prefer, if possible, to dump my holding tanks only once. I've successfully cleaned my sensors to read empty when the tanks are empty. My question: When the led light hits the full mark, how much more room do I have? We have a 2003 40-foot Phaeton with 70- and 40-gallon holding tanks. Share this post Link to post Share on other sites
wildebill308 Report post Posted September 27, 2015 Welcome to the forum. You have 2 very reliable indicators as to when your tanks are absolutely full. You can tell when the gray water tank has reached it's max capacity by looking in the shower, if you have water in the bottom of the shower and it won't go down your gray water tank is full. If you flush the commode and it doesn't go down, well you waited just a little to long to dump. Seriously are you at a RV park with hookups or some place where you have to move to use the dump station? If your tanks are filling up to fast you either have to dump or do a better job of water management. "My question is when the led light hits the full mark how much more room do I have?" To many variables between coaches. The only way you might come up with a number is to fill the tanks to where the lights show full then use a 5 gallon bucket keep adding till you reach absolute full. Bill Share this post Link to post Share on other sites
mikerodg Report post Posted September 28, 2015 Thanks Bill,Your suggestions are helpful. I'm sure we can improve our water management. Always anticipating boo docking for an extended period. At first I was surprised that the grey tank filled quickly. But then with 3 sinks, a shower and washer/ dryer it makes sense. We rarely use the washer dryer. We are in an RV park right now in Hilton Head. Since the process of dumping and cleaning the lines is tedious I'm trying to avoid doing it more than once in a week. We're going to gulf shores next and I will try the fill and 5 gallon technique in the black tank. It may be a bit much with a 70 gal grey tank but I like your suggestion of watching the shower basin. Thanks, Mike Share this post Link to post Share on other sites
wildebill308 Report post Posted September 28, 2015 If you have hookups leave the gray water valve open. It won't hurt anything and you can run the washer without overflowing your tank. I dump the black tank as needed. I like to add extra water before dumping then use the tank sprayer to make sure it was empty. I stayed at several campgrounds this summer that didn't have sewer at the site. You learn to be very water aware. Bill Share this post Link to post Share on other sites
hermanmullins Report post Posted September 28, 2015 We do as Bill said, we leave the Gray valve opened when parked for an extended time. However I always close it the day before we plan on departing. This allows for the tank to fill some to flush the hose after dumping the Holding tank. Herman Share this post Link to post Share on other sites
nitehawk Report post Posted September 28, 2015 On the Foreforum Website I recommended that everyone, at least once a year, fill each of their holding tanks up until their monitor reads "FULL". Doing this could prevent an unpleasant surprise when the tank overflows and still read 1/2. Verify your sensors are working and no surprises will blindside you. Share this post Link to post Share on other sites
mikerodg Report post Posted October 5, 2015 Thanks all, I used Bill's suggestion and tested the grey level. When the full light came on I started pouring water into the tub 2 gallons at a time. I stopped when I heard the drain fill up. Similar sound your gas fill hose makes when the tanks are full. I was amazed that I put in 18 gallons of water. That is a lot of leeway. Good advice and good to know. I did not try the black because it has not filled before the grey. Share this post Link to post Share on other sites
