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Your cart is empty.Sludge and soap residue build-up on the sides of RV black and gray water tanks can lead to false readings. The sludge acts like a conductor between the positive content level sensors down the tank to the negative probe that is located at the bottom of the tank. This will trigger the indicator panel to show that there is liquid level in the tank even when there is none. Horst Miracle Probes are considerably longer than standard probes and the sensor is surrounded by a Delrin body and Teflon tube which prevents any liquid residue or sludge from setting up a conductive path. The black tank probes have a specially designed “roof” over the probe sensor to prevent toilet paper from coming into contact with the probe and creating a false probe contact and related reading.
Dave
2025-07-19 16:18:26
Installed these in my RV gray water holding tank. They fixed the no read level issue, installed easily and fit Great!
Customer
2025-07-03 11:51:50
Disconnect the wires and I popped the old sensors out. I put a washer and the nut back on that was holding the wire then used a small pry bar and a wrench to pop them out. The plastic tank is tough, so no problem. It was a lot easier than drilling new holes.Installed the new ones, tightened them down, connected the wires, filled the grey tank, no leaks and its reading. My old sensors only read the bottom light.Highly recommended.U.S. Navy Chief (Ret.)
Neil
2025-07-01 13:38:33
The Horst Miracle Probes seem to be working great and the "tent" design protecting the sensor is genius, I installed them on both gray and black water tanks. The gray water sensors (first image) were easy to access and took about 20 minutes to install, however, my black water tank was a different story (second image). I can barely see those sensors and with limited clearance I struggled for quite some time. The three main issues I had were 1) trying to keep the sensor in the correct orientation while tightening down was near impossible without damaging the wire lug 2) the notched shaft was exceptionally difficult to start a nut on with my arm twisted around a corner and into a blind spot and 3) it was impossible to tighten the wire lug without disorienting the sensor. I struggled with the black water tank for several hours. As for my experience and opinion, if the design had some method of holding the sensor in the correct orientation while tighten the expansion nut and sensor wire I would call this product God's gift to RVers. My rating would be all 5 stars if the sensors were easier to install in limited clearance applications. I plan to install these on my fresh water tank but need to take a break from the frustration, maybe next month!
Andrew
2025-06-25 11:02:19
Ok so if your reading this and your like me you have had a hundred people tell you the tank sensors just suck and you can do all the things drive around with ice in the tanks bleach them flush them stand on your head under a full moon singing folk tunes and NOTHING works….. well I thought so to but I was WRONG. these things are freaking game changers! Why don’t the factory use these ? Anyway I chose to just drill new holes next to old sensors cut the wires new shrink tube fittings and then I covered the whole thing in clear flex spray silicone. This keeps the water and elements off the connections, but also an added layer of security that the nuts won’t back off on their own it locks the threads. I highly recommend getting these wish I had done it way sooner they work fantastic! I do alot of boondocking and knowing what the tank level ACTUALLY is and not guessing before you take aShower and wind up having it back up into the shower because you guessed wrong is a life saver! Note - the probes have little plastic sleeves on them do not remove ! The whole point is to not let the built up crap on the side of the tank make contact with the anode that’s why these are designed to stick out inside the tank. Also don’t try the “ice trick†if you have these installed ;) They are super easy to install yourself just follow directions and make sure you use the exact right drill bit 3/8†the hole has to be perfect so you when you tighten down the inner nut it seals itself sort of like a drywall screw into that plastic thing to hang a picture - perfect size hole. Otherwise it’s a cinch ! So glad I did this and well done guys who ever designed this ! Fabulous.
David K.
2025-05-19 14:58:23
I love these Valterra T21301VP Horst Miracle Probes. They worked great! My black tank readings were accurate all summer long; the sensors never lied. They were easy to install and they don't leak. I wish I had found these probes earlier so I wouldn't have had to guess about my black tank levels.
Chris
2025-04-12 18:51:47
These are the best sensors, I have been able to find for use on our camper grey tanks.They are accurate and easy to install.While you’re replacing the sensors, I would also recommend replacing the sensor harness at the same time.The factory sensors never read correctly, these read accurately and have not given me any false readings. If I have any issues in the future, I will come back and edit this review but don’t expect to have any problems with these new sensors, they have good reviews.
WeycoDave
2025-04-05 17:31:02
My OEM probes in my Thor Sequence were terrible. They were so inaccurate they might as well not even been there. I was constantly cleaning the tank, trying to get some sort of consistent/accurate measurement, but it was all a waste of time. These Horst probes completely solved my problem. I’ve been on several trips now & they have functioned perfectly (both the black & grey water tanks).
GW
2025-01-27 18:45:37
Installed these and they worked for about 1 month. Now they always read full. Horrible product. Do not buy. Can't return after it's been soaking in feces. . . .
Randall B
2025-01-23 17:01:27
Got this tank sensor pack to replace some old ones on our trailer. Drilled new holes to install in the grey tank and also installed new wire couplings for each sensor. I had hoped to reuse the existing wiring couplings but they were too rusted. Put on a dan of silicone on the nuts so they would not shake loose. The tank filled and the sensors showed accurate readings. Took around an hour to install. Very happy with these. Hope they last and keep performing well!
Tof masse
2025-01-13 10:20:50
Facile à poser. Et depuis mon niveau d'eau grise fonctionne. Je recommande.
Sask
2025-01-12 18:48:15
My original sensors were starting to have problems so I decided to go with these due to many good reviews. I watched a few videos to ensure that I was removing the old sensors correctly and how to install the new ones. In my case they fit directly into the same holes that the old sensors used. I was also fortunate that the RV had an access door for the valves and bottoms of the tanks so it was easy to get to the sensors. I replaced them late in the summer and they worked as expected.
Customer
2024-12-28 12:57:16
Easy replacement of existing sensors
Customer
2024-11-28 13:48:08
Easy to replace and fixed our misreading sensors on our black tank.
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