RectorSeal Calci-Free 68708 Tankless Water Heater Cleaner, Easy Application, Plumbing, 1.2 lb

Background you can skip: We have run our Tankless Noritz N0751 since 2008. We initially had the plumber come by yearly to do a flush at an outrageous cost and they used vinegar. 6 years in the unit would not kick in a fast, water flow was down and sometimes wouldnt even kick in. Plumber diagnosis: we have hard water and these units simply wont last long in that environment. Buy a new one for 3000$ for a retro fit install. I booted them out. Installed - should have done it years ago- isolation valves and used flow aide based on online recommendations. Ran diluted flow aide for one hour and came down to find the flush water black. The machine ran like new. Conclusion: Flow Aide > Vinegar, i.e. Flow Aide is better at cleaning than vinegar. However, flow Aide has gotten expensive. Recently I cleaned with the last bit of Flow Aide and when it ran clean I decided to try RectorSeal right after to see if it would still help. Whaddaya know, after 45 minutes i came down to find the water BLACK again. So my view is: RectorSeal > Flow Aide > Vinegar. Pros: Cleans well in well water / hard water environment. Our Nortiz Tankless is turning 15 with no end in sight. Beats the alternatives in effectiveness ... and in price Cons: None yet.

Really works. Effective.

Let me tell you about this magical little potion called the Rectorseal Calci-Free Tankless Water Heater Flush. First off, the name is a mouthful – it's like they couldn't decide whether to call it a flush, a descaler, or a fancy spa treatment for your water heater. When you open the tub, it looks like a batch of those fizzy bath bombs that are all the rage these days. But instead of turning your tub into a lavender-scented oasis, this stuff is going to give your tankless water heater the deep cleaning it deserves. And let's be real, those things probably need it after all the hot water abuse we put them through. The instructions are simple enough: dump it in, let it do its magic, and boom – your water heater is as good as new. No more weird buildup or funky smells when you turn on the shower. Just pure, unadulterated hot water goodness. Now, I know what you're thinking: "But wait, couldn't I just use some good old-fashioned vinegar for this?" Sure, you could. But where's the fun in that? The Rectorseal Calci-Free is like the spa day your water heater never knew it needed. It's like a deep tissue massage for all those hard-to-reach places. And let's not forget the best part: you don't even have to get your hands dirty. Just toss it in and let the little fizzy guys go to town. It's like having a tiny cleaning crew working tirelessly inside your water heater. So, if you're tired of dealing with mineral buildup and want to give your tankless water heater the royal treatment, do yourself a favor and grab some Rectorseal Calci-Free.

I did a flush on my propane on-demand water heater for the first time after 4 years of use. When I added this to the mix water in a 5 gal bucket, it off-gassed with a nasty smelling gas that I was not expecting, and I almost took a big whiff of it before I realized what was happening and turned my head away. There should have been a warning about that...be very careful of the vapors when initially pouring it into the water. The crystals then fell to the bottom, it has to be mixed in physically to dissolve all the crystals. Because it creates an acid solution, use a plastic bucket and plastic or wood to mix, do not use metal. I then ran this through my WH for 20 minutes as instructed. It went in clear and after 20 minutes I had an orangey-pink solution with some orange particles in the bucket. I used rubber washer hoses with brass hose ends. The 2 hose ends that were submerged in the bucket corroded during use, turned from a shiny brass gold to a dull grey color. I would consider the WH flush project a success, judging by how much scale ended up in the acid solution. Also, be careful how you dispose of the waste solution - it is a pretty strong acid so it will eat through metal, stone and concrete. I looked it up after the fact (should have done this before) and discovered it is just "sulfamic acid" crystals under a fancy trade name and in a fancy container. You can buy the same sulfamic acid off the shelf at a store for 1/3 the price, which is what I will do next time. Poor value for the money when you consider alternatives are readily available, but it was effective for flushing my WH.

Mix 2 gallons of water with it in a 2 gallon bucket and circulate it in your water heater following the instructions. It says to use for 20 minutes, but it'd been a while since I kept up with the routine maintenance so I ran it for 2 hours. You should've seen the water after. Definitely cleaned a lot from the tank. I'd hate to see what the pipes in my wall accumulate

I used this to perform a flush on my tankless heater. Much easier than vinegar.

Holy wow! Our water is high in Ca and Fe. The crap that came out of my water heater was brown and gritty. Great product! Works as described.

We spent $325 wasted money on a service call. The guy flushed it with vinegar which did nothing. With this product the water came out black. Now the heat is consistent. I think those people who say not to use it just want you to buy a new machine. Highly recommended. Too bad though it’s so expensive.

We have instant hot water heater & it needs to be cleaned to prevent hard water build up. We borrowed from a fried & replaced it with this product

Didn’t work well at all on my tankless on demand hot water Probably Get the same or better results using vinegar