8 Best Toilet Cistern Blocks of 2023

It is not uncommon that people get confused when they hear “toilet cistern blocks”. Not to be confused with “toilet rim blocks“, and as the name suggests, toilet cistern blocks are placed in the toilet’s cistern – the upper tank part of your toilet, where water is stored for flushing. They are also sometimes called “toilet cistern tablets” or “toilet blue blocks”.

Unlike other toilet cleaning products, toilet cistern blocks are very simple to install as they are simply placed in the cistern and left to work their magic, each time someone flushes the toilet – making them very popular indeed. Now there are many different products available in this category so we’ve gone ahead and rounded up some of the best toilet cistern blocks in the market that we could find. Enjoy!

Our Top Toilet Cistern Blocks Picks

1) Bloo In Cistern Twin Blocks

First up we have the Bloo In Cistern Twin Blocks with Long Lasting Anti-Limescale Cleaning. These cistern blocks offer superior foaming and cleaning action that keeps your loo shining and smelling lovely 24/7. Its excellent foaming action also prevents dirt and limescale build-up.

The product provides up to 2 months of freshness, with a single block lasting up to one month. Each block provides plenty of colourful water and amazing fragrance ensuring a deep clean for a long time. Simply position the block in the bowl, leave it for 10 minutes, and then it is ready to work.

Key Features

• Prevents the accumulation of dirt, germs, and limescale
• Produces long-lasting foam with each flush
• No need to unwrap the toilet in-cistern block
• The block is available in different colours and fragrances

2) Prism Ocean Scented Cistern Blocks

The Prism Ocean Scented Cistern Blocks come packing a powerful foaming action formulated to effectively freshen and clean your toilet with every flush. Just drop one tablet in the cistern for a hygienic, welcoming, and fragrant loo. These cistern blocks blast any limescale and dirt in your toilet bowl to leave it sparkling clean.

You will also get immense value for money, seeing that a single block can last up to 90 flushes. In turn, a single pack offer months of fantastic freshness. To top it off, these blocks are 100% biodegradable, water-soluble, and acid-free, making them both environment and family friendly.

Key Features

• Perfect for commercial or household use
• Prism Blocks offer fresh fragrances
• It contains potent cleaning agents that keep the toilet clean
• The blocks are wrapped in a poly wrapper to preserve freshness

3) Bloo Incistern Original Blocks

Keep your toilet immaculately fresh and clean with Bloo Incistern Original Blocks. These blocks have been manufactured to help prevent limescale build-up all around from the cistern to the toilet bowl. Available in a fresh blue water fragrance, you can be assured that your loo will be smelling great all day and night long.

Furthermore, the freshness of a single block can last for an entire month. To enjoy all the perks that this cistern block comes with, all you have to do is drop it in the cistern, and you are good to enjoy weeks of freshness and impressive cleaning action, all without any elbow grease.

Key Features

• Cleans and foams with every flush
• Long-lasting (up to 8 weeks of freshness)
• Prevents the accumulation of limescale
• Simple to use

4) Ecozone Magnoloo Anti-Limescale Cistern Blocks

Ecozone Magnoloo Anti-limescale Cistern Blocks are not your average loo blocks. Pvc rubber and magnets are the main “ingredients” of these blocks that give them a wow factor. They are a brilliant treatment for toilets, complete with magnetic power that softens water, removes watermarks, stains, and eliminates limescale without the need for harsh bleaches and chemicals.

To use these environmentally friendly cistern blocks, you only need to place a single Magnoloo block in your toilet after flushing the loo so that the water level falls in the cistern, and you will be good to go. Even better, you will be happy to learn that the product comes with a 5-year guarantee from the manufacturer.

Key Features

• Simple application
• Softens water to get rid of and prevent limescale
• Offers a prolonged cleaning solution
• Are effective descalers

5) Bloo In Cistern Twin Blocks Citrus Zest

With each flush, using the Bloo In Cistern Twin Blocks Citrus Zest leaves you with a spotlessly clean toilet as well as a divine lingering citrus fragrance. Its intense foaming action proficiently removes and prevents limescale and dirt, allowing you to sit back and relax instead of having to regularly scrub your toilet.

Grime formation will be a thing of the past with this cistern block, thanks to its germ-killing bleach formula. Each cistern pack allows you to enjoy two months of excellent foaming and cleaning action. Also, these blocks are packed in water-soluble wrappers and therefore you do not have to worry about unwrapping them.

Key Features

• Safe to use in septic tanks
• Cleans both the toilet bowl and cistern
• Provides tons of colored water to ensure an intensive clean
• Dirtproof and anti-limescale

6) Bloo In Cistern Twin Blocks Lavender

Give your loo a new lease on life with the Bloo In Cistern Twin Blocks in Lavender scent. These blocks have been formulated to disinfect your toilet from germs and kill harmful bacteria. In addition to preventing limescale, the twin blocks will also leave the room with an amazing Lavender fragrance with every flush.

The quick rinse formula spreads evenly and thoroughly cleans the bowl giving it a spotless sparkle. Users also love the violet toilet water that is produced with every flush, a welcome relief from the typical green and blue colours. Also, like other Bloo toilet cistern blocks, you don’t even have to remove the block’s wrapper because it will dissolve in water.

Key Features

• Offers excellent foaming and cleaning action with each flush
• Prevents limescale
• One block can last an entire month
• Gives your toilet water a lovely purply/pink colour

7) Parozone Strong In Cistern Blocks

A powerful bleach toilet cistern block, Parazone is just what you need to not only keep your loo clean but germ-free as well. This product has been manufactured to kill 99.9% of germs. By dropping a block in your cistern, it will quickly clean and foam with each flush for up to four weeks per block, which is eight weeks in total per pack. 

These Parazone Strong In Cistern Blocks can safely be used in septic tanks too, not just for toilets. They are very simple to install and are not unpleasantly strong smelling, like some bleach-based products out there. Remember to replace the blocks when the foam fades for continuous cleaning and germ-killing.

Key Features

• Available in 10 packs
• Kills harmful germs
• Can be used in septic tanks
• Keeps the toilet bowl clean and fresh

8) Bloo Flowers Rose and Apple Blossom In-Cistern Blocks

Another top product from Bloo, this is one of their cistern blocks that lives up to the promise of keeping your toilet clean and smelling fresh. You will not want to buy any other product after investing in these cistern blocks. They will not only clean your toilet, but they also foam up, leaving your loo with a unique pink colour to the water.

You do not have to worry about spending all your money on the blocks because it can last up to 8 weeks without a problem, 4  weeks per block. The scent of these blocks is a combination of Flowers Rose and Apple Blossom, which is a lovely and refreshing smell to add to your bathroom.

Key Features

• Prevents the build-up of limescale
• Produces pink water after foaming
• Leaves the toilet bowl shinning at all times
• You can use it safely on a septic tank

What are the best Toilet Cistern Blocks?

After researching all the greatest toilet cistern blocks online, we have found the best product to be the Bloo In Cistern Twin Blocks. This was because it was very popular online with over 3,000+ reviews, likely thanks to its powerful formula, low cost, as well as its effectiveness – plus not to mention that it is from a top renowned brand like Bloo. We looked at all the top retailers like Amazon, Wilko, Argos, Tesco, Sainsbury’s, Aldi, Asda, Tesco etc to check their cistern block range and reviews.

Are cistern blocks bad for the toilet?

Toilet cistern blocks, when used correctly, are not bad for the toilet. Manufacturers of high-quality blocks design them to help clean and disinfect your toilet with each flush. They are very convenient, helping users to save plenty of time when it comes to cleaning their lavatory. Additionally, they also produce lovely fragrances keeping the air in their toilet or bathroom smelling fresh.

Do toilet cistern blocks prevent limescale?

Yes, many of the cistern blocks listed in this article are designed to prevent and get rid of limescale. With that being said, naturally, other products on the market will vary and may prevent limescale. Most of the Bloo cistern blocks range are designed to prevent limescale, for example.

Do toilet cistern blocks actually work?

Absolutely, an excellent cistern block will work as it should. For weeks the blocks will keep your toilet clean, giving them a pleasant fragrance all day long. Many people who have used the blocks before swear by them, stating that they are essential loo cleaners that every household should have at all times. I myself use them and I couldn’t imagine not using them to be honest, due to the fact that they massively reduce the amount of cleaning I need to do myself!

Do cistern blocks damage toilets?

Many users have taken advantage of their cleaning and foaming power for years without any problems. To get the most effective results, it is best to follow the pack’s instructions to avoid any issues in the future. Furthermore, it is best to go for a top brand like Bloo where this is very unlikely to happen. As mentioned earlier, I use toilet cistern blocks and I have never had an issue.

Where do I put cistern toilet blocks?

As the name suggests you simply put them in the toilet’s cistern or tank. All you have to do is remove the toilet tank’s top and drop the blocks while it’s still in the wrapper. Place this on the opposite end of the handle or water inlet. See the video below for more information on how to use toilet cistern blocks.

Are toilet cistern blocks bad for the environment?

A few cistern blocks do not contain environmentally friendly material. However, there are many companies that produce the blocks that are at the forefront of taking care of the environment. Always double-check the manufacturer’s website to find out more before you buy.

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