Black tank flushers compared

[Nursx2]

fhenn - dude, watch the video on youtube.............it does nothing.

https://www.youtube.com/watch?v=q4GkSDnphvU

[fhenn]

Did not say it would remove solids, It removes the paper from the sensors.

[Nursx2]

OK, my bad!

[FW28z]

I did like that video though... with the guy driving like he was in a NASCAR race.

[Nursx2]

I agree - imagine driving your motorhome down the road like that! I think it would work better if the tank was 3/4 full of water, maybe!

[JamieGeek]

Originally Posted by Nursx2

imagine driving your motorhome down the road like that!

Really? You don't drive your RV down the road like a maniac?? LOL I thought everyone did. (The creators of the video may as they have a smallish motorhome from what I could tell in their other videos.)

I wonder if the ice trick would work a little better in a trailer/5th wheel since they tend to bounce around a bit more than a motorhome (no shocks and a good pivot point right in the middle).

[FW28z]

Well, I do have a bit of steering wander...

[JamieGeek]

This all reminds me: Last year we were returning home from a camping trip when an older camper (a small 20ft or so trailer) about 4-5 cars ahead of us "shed" some parts.
Fortunately I was far enough back that I could easily avoid the carnage. When we passed them I could see what had happened: All of their waste tank plumbing had disintegrated. The only thing left was the two tanks with respective holes in them where all the plumbing was--easy cleanout now! From what I could tell they must have hit a bump and the lowest point of the drain plumbing had hit the ground (it was all at the rear of the unit). They continued on not knowing what had happened..I'm sure they got a surprise when they reached home!

[EdTheEdge]

Originally Posted by fhenn

You can dump a bag of Ice cubes into the toilet and drive down the road. I do this a couple of times a year, and it seems to clear the mess away.

Interesting.... Might give that a try.

[FW28z]

Well, I have done a bit more research on the tank monitor systems. The typical monitors are made by a company called KiB Electronics in where else... Elkhart, In.

The "sensors" for the tanks are nothing more than a bolt inside of a rubber grommet, wherein when the bolt is tightened, the grommet expands to seal the tank.



There are 4 such bolts in each tank. The bottom most bolt connected to ground, then the upper three bolts at approximately the 1/3, 2/3, and top levels of the tank.

These bolts are then connected to a "resistor ladder" network between the ground bolt and the three upper bolts. This allows a variable resistor of sorts, as the bolts under the current liquid level is shorted to the ground bolt, more or less.

I see several potential issues here.

First, water is actually an insulator. At least pure - distilled water is. What makes water conductive is the particulate matter found in tap water such as minerals; and for a holding tank, it's organic contents as well as any enzyme or other additives.

This means the conductivity of the water can vary significantly, which in effect, does change the resistance readings the resistor network provides. However, with only 4 data points (empty, 1/3, 2/3, full) in the monitor system, the tank reading is not all that accurate anyway, so this may mask any error associated with the variable fluid conductivity.

Secondly, and probably more important, the bolts protrude into the tank, which is I believe where most of the problems come from as tissue or other matter could potentially cling to the bolts, thereby creating a false reading.

The third issue I see is even an empty tank will be wet, which can affect the reading until the tank sides dry out, especially if it is wet/dirty water.

In my experience, the fresh water and grey water tanks in my coach do not generally give me as many problems as the water is cleaner, and perhaps not as affected by the particulate matter suspended in the liquid.

In contrast, the tank monitor system I had in my boat, which was very reliable, was an external sensor system, with no components to protrude in the tank. The sensors worked on the principle of capacitance, wherein the capacitive value between two vertical metallic strips changes in accordance to the fluid level inside of the tank.

The advantage of an external system is there are no components to foul, nor is the accuracy particularly affected by fluid contents. And there were 10 or more data points to the scale if I recall.

My first solution is to try and get a fresh water flush system installed, and especially locate it so that will spray water on the bolts used for the monitor sensors. If I can keep them clean, perhaps the tank monitor will not give false readings and I won't have to proceed further.

If that does not work, I am looking into the feasibility of adapting those sensors to the KiB monitor display, at least for the holding tank. I am very confident I can do it with ease, but my major hurdle is I would have to run a power wire to the sensor as they are active. As well, I am concerned about battery drain as the sensor and conversion circuit will take some power from the system.

Whether I can get the system to turn on when readings are taken - then shut off between readings to conserve power is probably going to be more of a challenge than interfacing the sensor.

I should contact the guy that did the videos and encourage him to do the experiments with 4 of the KiB bolts in the tank, and see how or if they foul.

[JamieGeek]

Well here you go, more research LOL! A nice long article about the different ways to measure fluid level in a tank (more for industrial processes though but nevertheless a good overview):
A Dozen Ways to Measure Fluid Level and How They Work | Sensors

Here is a DIY capacitive level sensor project:
http://www.instructables.com/id/Buil...nsor/?ALLSTEPS

Since it is using an Arduino microcontroller it should be pretty easy to have the Arduino ground the 3 tank probe pins to light up the levels on the RV's panel (assuming that the "bottom" probe is connected to ground and the fluid in the tank just grounds the probe when in contact).
Hmmm

[FW28z]

Thanks for the link.

[blw2]

FW28Z, here the supposed answer for RV tanks
I doubt that it would be quite as reliable as the external capacitance type, but these are supposed to be the answer to replace the screw probes in an rv tank
Horst Miracle Probes for Wastewater Tanks in Recreational Vehicles RVs
I have read quite a bit about them on other forums, but have no 1st hand experience..... yet.
Then there is the "gold standard" SeeLeveL Gauges by Garnet Instruments Ltd. - RV Applications

[blw2]

Originally Posted by FW28z

...I should contact the guy that did the videos and encourage him to do the experiments with 4 of the KiB bolts in the tank, and see how or if they foul.

I would like to see that.
I enjoy his vids and have watched most all of them. Not perfect analogs in many ways, but still very interesting and I think they do a decent job of showing what is going on.

[FW28z]

Originally Posted by blw2

FW28Z, here the supposed answer for RV tanks
I doubt that it would be quite as reliable as the external capacitance type, but these are supposed to be the answer to replace the screw probes in an rv tank
Horst Miracle Probes for Wastewater Tanks in Recreational Vehicles RVs
I have read quite a bit about them on other forums, but have no 1st hand experience..... yet.
Then there is the "gold standard" SeeLeveL Gauges by Garnet Instruments Ltd. - RV Applications

Two boats ago, I had this type of tank sensor:



It was an in-tank sensor with a capacitive monitor consisting of two wires running down the tube. After two years or so, the one in the black tank had quit working, and when I took it out to look at it, the entire probe was discolored, and looked like it had burned. Of course, it was from the tank contents, and probably a chemical burn. It was not an electrical issue.

I never had a problem with the fresh water tank sensor. Again, I am sure there is some very nasty stuff in the black tank once the organic matter starts mixing with the tank chemicals.

At the time, this was the most popular monitor in boats, and my experience was common, so much so that many boat owners were ripping them out, and many companies quit OEM'ing them in new boats.

I think the real issue is to keep the sensor out of the tank - especially for the black water tank as there is some awful stuff in there.

I was going to replace the system, but ended up trading up to a larger boat, so I simply replaced the sensor to give the owners another 2 years of use.

In my last boat, I installed the "New Providence Marine" tank monitor system. These guys invented the outside foil strip capacitive sensors, and I had it for the 7 years I owned the boat without any problems.

I am convinced though that the only sensors that are reliable are the external tank sensors - especially for the black tank. But that can bring up another issue in that my black tank is exposed to the underside of the RV, so if the sensor gets road salt or grime on it, it can fail. I am thinking that the best solution to that is to spray some conformal coating on the sensor.

But even if it can fail occasionally, if the Horst system proves to be more reliable than the KiB system, it would at least be an improvement. I'll have to investigate that system a bit more. It seems simple enough, and simple is good. Thanks for the link... I'll check into it as well.

The Garnet system's sensors look a lot like the sensors I used in that they are external to the tank. I did talk to one of the big wigs the other day from New Providence, and he was telling me about other companies stealing their patent. He did not go into details though, and since these are often small companies, I am sure it is cut-throat and they might not be able to afford the legal fees for such things. Of course, this is his perspective, and I have no way to determine if this is so or not.

He is going to send me one of their sensors so I can test it.

If I can't get the thing to work with the existing system, I might have to rip the old one out and simply install the complete New Providence system.

This is the one I installed in my boat in 2006:



I am sure there is a new model out by now.

The beauty of this system is it can monitor many different sensors, both the foil one they supply, or some 3rd party ones. For example, the monitor I had consisted of 8 tank channels. I used two for the fresh water tanks (I had two tanks on board), one for the black water tank, and one for the toilet deodorizer tank, all of which had the foil sensors.

Then, I had two gas tanks (that held a whopping 85 gallons each), and the monitor system simply paralleled the resistive automotive style gas tank sending units.

The monitor system could also monitor LP gas monitors, and it also monitors voltage, so it can directly replace all of the functions of my KiB monitor system. Only thing is, the KiB system costs probably about $100, but with the sensors, the New Providence system is going to cost about $500.

I didn't have 8 tanks so I only used 5 of the 8 channels. But the unused channels simply stayed off line. The monitor is also programmable so you can adjust the set points, set the tank shape, which tanks have alarms, and even it could display the boat's name if you wanted it to.

Some things I did like though about the New Providence system. The LCD had a bar-graph readout for the tank level, and gave a % full reading. It was analog, so it gave precise readings. You could also attach an alarm for when the tank was either full or empty, or no alarm on that tank channel.

If I end up ripping the old tank monitor system out and install this one, I will also make a new custom monitor panel so I can transfer the generator control and the other switches such as the slide out, water pump, hot water start, etc. That way, it will look custom rather than having a non-functional panel.

[blw2]

exactly what I would love to do.
I know that many argue that it's simply not that big a deal to let the tank indicators fail and go on visual indicators, or learn how long you can go....
I just hate the idea of having something installed that doesn't work. It really bugs me. I could never install a new panel and leave the old 1/3-2/3 lights in place.
I'll bet you're the same way.

right now I have on my list of things to do to trace out the LP indicator..... the dummy lights read full, while the mechanical gauge indicates the real level down to 1/4 where I refilled it. I need to get time to dig into it. Don't need the lights, but it bugs me that they don't work.....

[FW28z]

Looks like the Horst probes are out of stock. But I do like the idea of just replacing the probes and keeping the rest of the system intact. They cost about $30 per tank, when they are available again. I am going to order a set.

[JamieGeek]

Having read a bit about how the capacitive sensors work I think I can upgrade the current panel to capacitive using a microcontroller for less than $50.

Good point about road salt/grime since most tanks are underneath and exposed.

[FW28z]

Originally Posted by blw2

exactly what I would love to do.
I know that many argue that it's simply not that big a deal to let the tank indicators fail and go on visual indicators, or learn how long you can go....
I just hate the idea of having something installed that doesn't work. It really bugs me. I could never install a new panel and leave the old 1/3-2/3 lights in place.
I'll bet you're the same way.

right now I have on my list of things to do to trace out the LP indicator..... the dummy lights read full, while the mechanical gauge indicates the real level down to 1/4 where I refilled it. I need to get time to dig into it. Don't need the lights, but it bugs me that they don't work.....

Yep, I am exactly the same. In fact, my monitor panel has an unused switch for a 120V water heater element, and two blanks for the tank heating pads, as I don't have those options... that bugs me, so much so that I am thinking of adding those functions.

My wife thinks I am crazy.

I tell her since I am retired, I have nothing else to do.

As for the tank level not being a big deal... I can assure you if you have an overflow, it isn't pretty. This happened once on one of my boats where the tank overfilled. Of course in a boat, if the tank overfills, it's much worse as it goes directly into the bilge rather than on the ground.

Even so, I like to keep from overfilling the tans in my RV, if not for anything else than environmental issues, not to mention "bubba" and his clan in the RV parked downhill from me at the campground.

Between the holding tank dumping and rinse, as well as the Siphon 360 roof vent I installed for the black tank vent, I have not had any smell issues at all in the bathroom of the RV. Again, this was a big issue in boats and boaters continuously have to fight against those odors.

In the boating world, there is an industry expert - Peggie Hall (she calls herself the "head" mistress), that knows everything about marine sanitation. She is not only a consultant to the marine industry on sanitation issues, She started a marine sanitation company which eventually became part of Raritan. I corresponded with her a couple of times over the years via email. I even bought an autographed copy of her book.

Long story short, I like to educate myself when encountering such issues, and marine/RV sanitation is so exciting (not!). But when we were at the boat dock, we had one of the few boats that did not have a stinking head. And so far, we have had no stink issues in the RV (at least from the bathroom)... due to my odor management skills

[blw2]

Originally Posted by FW28z

My wife thinks I am crazy.

You are....
.... from one crazy person to another....