Crud in black tank? December 14, 2024, 03:12:32 pm Hi all—our new to us 2007 23 1/12 twin-king has a poorly maintained black tank that I cant seem to get clean. The unit spent most of its life in Florida and was connected to well water that had a high mineral content. Consequently, there are lots of deposits in the tank that i can’t seem to clean up. Large pieces of hard mineral deposits will break off occasionally and clog the outlet. I can put my hand up in the discharge pipe and feel the rough deposits. The buildup keeps the tank from the nice forceful woosh that takes all solids with it. Much flushing with a hose is required to move everything and the drainage is slow. I have tried letting LimeAway soak for weeks followed by gallons of white vinegar to no avail. Does anyone have any suggestions as to how I can dissolve/clean up this tank short of replacing it? Thanks for any and all input.
Re: Crud in black tank? Reply #1 – December 14, 2024, 04:17:47 pm Have you tried a good flushing using a flushing tool dropped down through the toilet? Hard water deposits do not stick well to plastic tanks and should be released when hit with a high-pressure water jet. You might consider removing the dump valve to allow better access for cleaning from the large opening, using a flushing wand.Amazon.com: Valterra A01-0184VP Master Blaster RV Tank Cleaning Wand with...Larry 1 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Crud in black tank? Reply #2 – December 14, 2024, 04:22:34 pm In addition to Larry’s advice, if all else fails you might give Kleen Tank a call. See if they can help. Kleen Tank, the nationally-recognized, independent RV tank cleaning serviceBest of luck with this aggravating issue. 1 Likes
Re: Crud in black tank? Reply #3 – December 14, 2024, 04:35:59 pm Quote from: Ed & Margee - December 14, 2024, 04:22:34 pmif all else fails you might give Kleen Tank a call. See if they can help. Kleen Tank, the nationally-recognized, independent RV tank cleaning serviceI have watched a Kleen Truck clean the tanks of a friend' LD. They use a pressure washer and various attachments to pressure wash the interior of the tanks, it does a good job.With the use of in-tank flushers and a once a year soak with septic tank enzymes, our 22-year-old tanks stay clean and clog-free.Amazon.com: Camco Tornado Rotary Tank Rinser Features a 6-foot Hose,...Holding tank flusher | FlickrLarry 1 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Crud in black tank? Reply #4 – December 14, 2024, 05:01:06 pm Yes, I have used a tank wand with full pressure without success. Hard water deposits remain. I will contact Kleen tank and see what they say. In the meantime, I was hoping there was a chemical solution that would help.
Re: Crud in black tank? Reply #5 – December 14, 2024, 05:41:06 pm Perhaps you may want to investigate this product. No experience outside of the home but may help with hard water deposits in a black tank!CLR Calcium, Lime and Rust Remover | CLR Brands
Re: Crud in black tank? Reply #6 – December 14, 2024, 05:53:24 pm Quote from: Chartrue2 - December 14, 2024, 05:01:06 pmYes, I have used a tank wand with full pressure without success. Hard water deposits remain. I will contact Kleen tank and see what they say. In the meantime, I was hoping there was a chemical solution that would help.There is always a few gallons of pool acid mixed into a full tank of water. It will break down hard water deposits but can be dangerous to use.Lime-a-way is a weaker acid, it would take many pounds of it to dissolve the deposits in the tankGood luck.Larry 1 Likes
Re: Crud in black tank? Reply #7 – December 15, 2024, 08:28:55 am Just a thought here, since the tank you are dealing with is flexible plastic, could you gently tap the outside of the tank with a rubber mallet and then flush. I would think most scale attached to the walls would fall off from the flex of the tank.Jon 1 Likes
Re: Crud in black tank? Reply #8 – December 15, 2024, 08:52:24 am If the tank is usable, what might end up doing it is time. A few trips with different water filling it up and bouncing around, it might fix it's self.
Re: Crud in black tank? Reply #9 – December 15, 2024, 01:58:51 pm I've heard of, but not tried both ice and or rock salt. Floating in a partially full water tank and driven vigorously over a few bumps and turns. In your climate the ice might work. In my more temperate climate, ice wouldn't last as long. The advantage here is that both salt and ice would dissolve/melt and not permanently clog up the works. A variation on that would be warm water with some soap. Not over about 140 degree water, but chemical reactions happen faster at warmer temperatures. Even some sharper 'pea' gravel might help also, but you would have to make sure to get it all out. The advantage is more mass with sharper edges. But of course you would have to dump that on the ground, not into a plumbing system. RonB
Re: Crud in black tank? Reply #10 – December 16, 2024, 10:03:23 am Don't waste time and money on ice in black tank -- spoiler alert it don't work.Does ice in your holding tank really work?For a hard water mineral built up in a black tank only something is not making sense. The built up would be in both tanks and also the plumbing. Water sits in the fresh water tank longer then waste sits in the black tank. Urine and feces has all sort of mineral in their content. Dried feces can be hard to remove but it's water soluble. If there is no problems in the fresh water tank then I'm guessing you have another issue. glenedit .......PS just remembered hot water tank.If you have problem no issues with the hot water tank (this is were mineral problem would show up first) then you really have an issue of another sort. 2 Likes
Re: Crud in black tank? Reply #11 – December 16, 2024, 02:40:42 pm Water, just a small amount of residue left in a black tank after dumping, can dry up and leave mineral deposits. The water in Florida is generally pretty 'hard' in that it contains calcium chloride and magnesium chloride. The white deposits sound like calcium and magnesium plaques that could build up. (Calcium is more brown/beige). Once deposited, those chemicals don't re-dissolve well. I would use a gallon of 'Muriatic' acid, pool acid used to keep hard water deposits under control in pools. Really hydrochloric acid, it is inexpensive, and should work well to clean the insides of tanks. If the fresh water tank is left wet, it won't deposit in that tank or piping. It will collect in the water heater because of the heating. That is the white stuff (magnesium) left in that tank, and in the diffuser small openings in the faucets, hot water outlets. The reaction yields hydrogen gas, so no open flames or sparks. Handling acid is always problematic. Gloves, eye shields, etc. Thumping the bottom of the black tank might help the acid penetrate and infiltrate the large chunks that you seem to have. The gray water tank might have similar built up layers inside. RonB
Re: Crud in black tank? Reply #12 – December 16, 2024, 03:39:45 pm Some type of acid is needed to break down the deposits. Besides muriatic acid, high-strength vinegar could be used.It is available in up to 75% concentrations.Amazon.com : 75% Vinegar | Detox Health Products | Pure Super Concentrated...FYI, a 30% concentration of vinegar loaded into a spray bottle works great for spot-killing weeds.If acid doesn't work, the tank can be dropped for better access to its interior. Thumping the tank with a rubber mallet on all sides should break up acid-weakened deposits. Replacing the tank would be very expensive, needing to be custom-made at a plastic fabrication shop, with new inlet and out fittings welded in.Larry 1 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
Re: Crud in black tank? Reply #13 – December 17, 2024, 08:59:57 am Thank you to all responses. The battle continues!
Re: Crud in black tank? Reply #14 – December 17, 2024, 11:56:28 am QuoteReplacing the tank would be very expensive, needing to be custom-made at a plastic fabrication shop, with new inlet and out fittings welded in.I had to replace a black tank maybe 8 or 10 years ago. At that time and I imagine still, you could get one made to your specs in Elkhart, IN. As Larry said, it is pricey but it can be done. Regarding the holes (at least on my tank), you just use a big hole saw to reproduce the inlet and vent (outlet should be done by maker), insert new rubber grommets (or your old ones) and slide the tank up onto the toilet outlet pipe. I sure hope you can overcome this issue without resorting to this! jor* I wonder if Todd might have drawings of the waste tanks?
Re: Crud in black tank? Reply #15 – December 22, 2024, 08:55:38 am The saga continues—after much dumping, rinsing, many different chemicals and pressure washing, the black tank now looks clean, but continues to break off pieces of mineral deposits. Yesterday, while dumping, a large piece broke loose and clogged the discharge opening. Tank would fill up and would not drain. Luckily, with the use of lots of water and opening and closing the dump valve many times, the piece became dislodged and we had success. I guess that after 17 years of misuse, it will take some time to get it back to normal. Waiting on delivery of some 80% vinegar which is the next step. Thanks for your input! 3 Likes
Re: Crud in black tank? Reply #16 – December 22, 2024, 07:46:39 pm Quote from: Chartrue2 - December 22, 2024, 08:55:38 amWaiting on delivery of some 80% vinegar which is the next step. Thanks for your input!Do be cautious with the disposal of the used vinegar. 80% is used as a weedkiller, so it has the potential to disrupt a septic system if that's what you're dumping into or killing local foliage if it spills.
Re: Crud in black tank? Reply #17 – December 23, 2024, 07:10:01 pm Get a price on black tank replacement. Should not be that bad a replacement since it is plastic. Replace the valves and hoses as well. Just cut her out and slip in a new one. Easy dumping from then on!Ron S
Re: Crud in black tank? Reply #18 – December 23, 2024, 08:22:29 pm Hi Chartrue2; 17 years allows for the deposition of many layers of magnesium, and calcium from hard water allowed to dry out in thin layers. My T/K is pretty uncomplicated. I dropped a nut in my cleaned out black tank (fortunately cleaner than normal) and it fell out when I pulled the gate valve open. A long wooden dowel, maybe 3' long should be able to break up anything big enough to clog up that tank. An aluminum dowel would be easier to clean. A small pointy end should be able to break up any of those flat pieces. Vinegar is just too weak. Pool acid, (HCl) and CLR. More effective. Sold as hard water deposit and drain cleaners. Don't mix it with water in the tank. You want the chemical activity in a thin layer at the bottom of the tank strongest where the deposits are. I doubt that there is any build up on the sides of the tank. OK, after years and years of actively handling many even more deadly chemicals. I'm used to the concept. RonB
Re: Crud in black tank? Reply #19 – December 24, 2024, 09:16:07 am Thanks Ron! I am making progress with each dump. I can see the bottom of the tank through the toilet and can see that the deposits have broken up on the bottom. Still dealing with deposits around the neck of the discharge. I will continue with Lime Away and CLR. Slow and steady will win the race. It may be an easy replacement of the entire tank, but not for this 80 year old man! Merry Christmas!! 2 Likes
Re: Crud in black tank? Reply #20 – December 24, 2024, 03:08:34 pm Merry Christmas, and replacing that tank is really unnecessary. The layers of deposit that precipitated onto the bottom will eventually break up and be emptied. I might shine a light through the toilet while the tank is cleaned out, and breakup as much as possible with a thin pole. An aluminum dowel about 1/4" would be easy. Don't damage the rubber seal on the toilet flapper (looks like a ball valve). RonB
Re: Crud in black tank? Reply #21 – December 24, 2024, 03:28:05 pm Quote from: Chartrue2 - December 22, 2024, 08:55:38 am Waiting on delivery of some 80% vinegar which is the next step. Thanks for your input!Considering I have used 5% vinegar to clean our coffee maker for years to break down calcium deposits, an 80% solution should work fine to help break up your tank deposits.Fill the empty tank with as much vinegar as you have and let it sit for a few days to work on the deposits in the bottom of the tank before filling the tank to dissolve deposits on the side walls.As Ron mentioned, using a stick to mechanically agitate the insides of the tank through the dump valve and down the toilet is a good idea. For better access, remove the dump valve for a straighter shot into the tank.Larry
Re: Crud in black tank? Reply #22 – December 24, 2024, 07:23:38 pm After a long acid soak, having a Kleen Truck blasting should end your problem. They specialize in cleaning badly maintained tanks. Ask if they use a remote camera to view the tank's interior to make sure it is completely clean, your problem is unique and unlike their normal jobs. I can't remember previously hearing of this issue.Larry
Re: Crud in black tank? Reply #23 – December 24, 2024, 08:26:09 pm QuoteAsk if they use a remote camera to view the tank's interior to make sure it is completely cleanAlso, anyone who wants to take a peek in there can pick up an endoscope from Amazon. They are cheap, use your cell phone for control, screen and recording and have a powerful light. jorendoscope 2 Likes As an Amazon Associate Lazy Daze Owners' Group earns from qualifying purchases.
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