Bloo 3in1 In-Cistern Toilet Blocks Original, Pack of 4, Limescale Remover Cistern, Cleaner with Cleaning and Foaming Action, Fresheners

I live on a chalk hill. It's an aquifer and my tap water comes from the deep reservoir within it - which is why my tap water always comes out chalk white! I have to run it for some time for it to become clear. It deposits lots of limescale into everything that needs a water supply, including my toilet and cistern.Nothing has worked well enough to remove much of the limescale that's built up in my cistern and toilet bowl too (to a lesser degree), despite many products and much scrubbing. The flush has even become less powerful over time, from the limescale I can't reach! I bought these Bloo cubes on a whim, purely because I'd not tried this particular Bloo product yet. I'm constantly searching for anything to do the job better. These turn the water blue and smell nice. It's a clean smell and not overpowering when the loo is flushed either. It's just enough for the bathroom to smell nice. I suppose it could smell stronger but it's not the smell I'm interested in, as long as it's not a choker.Less than 24 hours after popping one in the cistern I noticed the limescale was reduced and within 1 week the flush was more powerful! I couldn't believe it. One cube lasted us 5 weeks in total and during week 4 the flush was really good, flushing almost as well as it used to!The toilet bowl is definitely not coated in as much limescale either, it's more shiny and definitely smoother. It also helps keep the toilet clean after use, meaning now it just needs a quick clean daily and a weekly scrub. As the only cleaner in my household this is definitely a good thing!As you can likely tell, I'm very pleased with this product and I hope it works as well for other people. I had a lot of scale to remove compared to a lot of other toilets I've seen or cleaned, but I assume it'll work well in a situation with less scale, although perhaps it might not be as noticeable as the changes I've seen.There's a green Bloo cube that keeps away limescale. I've not tried that yet as I'm still on my 2nd blue cube (not as much of an improvement to report as the first cube used), but I'll certainly consider it after this cube has finished. I'm hoping it'll maintain this this reduced level of limescale. If not, I'm back to these blue Bloo cubes... until I find a better product!

Having tried so many, I just fall back on these. They actually work and last reasonably well. Easy to use and give a fine result.

Having used a wide array of toilet maintenance products over the years—from gels and discs to fizz tabs and bleach solutions—Bloo’s Original Blue In-Cistern Blocks immediately stood out for their sheer convenience and visual satisfaction. Drop it in and forget about it for several weeks? Easy. But as someone who maintains properties professionally and pays close attention to what happens beneath the surface, this little blue powerhouse isn’t without its warnings.First off, yes—it works impressively well on the surface. Each flush releases a rich blue swirl that’s both satisfying and clearly doing something. You notice less limescale build-up in the bowl, odours are kept in check even in high-use households, and there’s a clear foaming action that suggests it's actively cleaning. Over the course of four weeks, one block handled hard water scale, toilet rim residues, and that unspoken bathroom film with noticeable efficiency.However, the hidden trade-off? The inner cistern. After two months of back-to-back use, I noticed something odd in one client’s WC. The toilet began leaking from the base, and upon inspection, the flush seal (a rubber component that forms part of the siphon or flush valve) had deteriorated badly. It was softening, cracking at the edges, and had absorbed an unusual blue tint. The water left in the cistern had taken on a slick feel—almost slippery like a light detergent solution. Testing confirmed what I suspected: the active components, particularly the colourant and limescale agents in Bloo’s formulation, had gradually compromised the rubber seal integrity. The replacement cost wasn’t high, but for those with older cistern parts or non-standard fittings, it’s something to be aware of.Professionally, I now only recommend Bloo blocks in toilets where the cistern has synthetic seals (silicone or PTFE based) or where routine maintenance includes seal inspection every 6–12 months. For more delicate or rarely inspected cisterns—especially those using rubber-based drop valves or older flappers—these blocks can gradually degrade key internal parts. It’s not immediate, and many users might never notice, but it’s a hidden risk if left unchecked.On the plus side, the formulation is potent. It truly does reduce limescale over time, particularly if you're in a hard water area. The scent is crisp, not overly chemical, and the deep blue dye gives visual reassurance that the product is still working. It’s incredibly easy to install—no unwrapping, no fuss, just drop it near the float and you’re done. Each block lasted about 3–4 weeks in standard flush use and up to 5 weeks in a downstairs cloakroom with lower footfall. In terms of presentation and user-friendliness, it’s a winner.Pros:– Powerful limescale prevention and surface cleaning– Long-lasting (800 flushes per block is realistic)– Excellent value, especially in multipacks– Colour-changing indicator lets you know when it’s time to replace– Easy installation with no unwrapping required– Keeps the bowl fresh and blue between cleansCons:– Can degrade rubber flush seals and gaskets over time– May cause unexpected leaks in older or sensitive cistern systems– Slightly greasy chemical feel to the water in the tank– No protective casing or child-safe packaging– Not suitable for macerators or wall-hung units without regular maintenance accessFinal thoughts: If you’re the type who wants a hands-off toilet cleaner that works visibly and doesn’t smell like hospital bleach, Bloo Original Blue is excellent—as long as you’re aware of the caveats. I’d advise using it with caution in high-end toilets or those with older plumbing. And if you're in a rental or managing multiple properties, periodic checks on seals and internal cistern fittings are a must.It’s a five-star performer when judged solely on cleaning power and convenience, but loses a star in my book due to the potential for long-term damage. A great product, but with a reminder: what it cleans in your bowl may wear away what’s behind the scenes. Use smartly.

Great product . Use them all the time . Nice smell and cleans well .