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Mr Crystal Concrete Tank & Trough Repair Kit

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Mr Crystal Concrete Tank & Trough Repair Kit is the simple answer to repairing all those leaking concrete tanks and troughs. It is safe for drinking water tanks.

Mr Crystal is a cement based waterproofing compound that chemically reacts with moist cement based substrates forming insoluble crystals in the capillary tracts of the substrate waterproofing the concrete yet still allowing the surface to breathe.Whether they be on your farm, small property or even a household block, Mr Crystal will provide the means of easily repairing any leaks you may have in any concrete water holding structure.

Mr Crystal comes as a full kit to enable you to repair your concrete tanks and troughs with ease.

Mr Crystal is applied to the surface of the concrete. Within concrete are millions of tiny voids. Mr Crystal migrates through these voids by osmosis and capillary action, generating in-soluble crystals as it travels. Mr Crystal is in fact a catalyst, which causes your existing concrete to grow in-soluble crystals. This means you have a large amount of material in the structure, which can generate in-soluble crystals without adding material that will expand cracks. Mr Crystal is stimulated by the by-products of your existing concrete and hydration. This means, each time water is present within the substrate, Mr Crystal will activate.

How does it protect the reinforcement?

Mr Crystal protects the reo in two ways. Firstly, it protects the reo from the elements by excluding water and air from reo tract. Secondly, Mr Crystal chemically protects the reo by restoring the alkalinity of the substrate thus reducing the acidity of the environment in which the reo is located.

Limitations of the product:

Mr Crystal is designed to work on commercial grade concrete that has basic structural integrity. To achieve success with this product you must ensure that, structure is made of concrete containing building cement (commonly known as Portland cement). Movement must be controlled by adequate foundations and reinforcement and finally the structure must be treated according to the enclosed directions for use.


1 Kilogram will treat 4.5 metres of crack.

Surface Preparation:

Apply to cement based surfaces that are free from dirt, dust, grease, oil, efflorescence and other contaminants. With tanks and troughs you can use a scraper and wire brush. Using an angle grinder will give fast accurate results. With a grinder, remember, you are not trying to cut concrete, just "bullying" the contaminants off the surface. Structure to be repaired must have basic structural integrity. Clean out and patch cracks larger than 0.25mm thick with a sand and cement render. Use caustic soda solution to clean oil contaminated surfaces then thoroughly hose down to completely remove contamination. Wet down thoroughly the surface to be coated immediately prior to application.


For best results, apply Mr Crystal when outside temperature is between 10C - 25C.


Mix only the amount that can be used in 10 -15 minutes. Mix .5–1kg with water and bring to a thick paste. Mix thoroughly and add water or product to bring the mixture to a thick creamy, yet just paintable consistency. The final ratio should be about 1kg powder to 375 mL water.


Mr Crystal can only be applied to wetted cement-based substrates (splash some water on the crack as you go). Apply a strip of mixture 60mm wide with the enclosed brush directly over the crack, working the mixture well into voids. To prevent segregation and keep a uniform mixture stir the mixture frequently during the application and dip brush deep into the mixture so that a thick coat can be applied. You may notice that the first coat appears patchy. As this first coat begins to go tacky, apply a second coat. The "tacky" first coat will "grab" the second coat enabling you to build the mixture up to a total of 6mm thick.

Where to apply Mr Crystal:

Mr Crystal can be applied over or adjacent to cracks, suspected weak points, cold joints, porous surfaces, around fittings. Mr Crystal can be applied to either side of the face of the concrete. Mr Crystal migrates through the voids in the concrete and has been known to migrate up to 400mm from the point of application. The resultant crystal growth is the waterproofing effect of this product. The raw product itself is not waterproof (in fact, it is highly absorptive by design).

When applying Mr Crystal where there is flowing water, remember not to be too concerned that some product may wash off. It is important to focus on the intact material (that hasn't washed off) to ensure that it is correctly applied, cured and stimulated.

Tip: If the water is running down a vertical crack and washing the material off try this. Take some short drinking straws, squeeze one end into the crack and leave at a sharp downward angle. This will take a good bit of the water away from the wall. A piece of tie wire with one end flattened will also be effective. Even a shovel or hammer handle leaned against the leak will divert some of the water away from the area to be treated (much like how water runs off the end of your finger in the shower) They can be removed as product hardens.


Protect the surface from rain or frost during initial cure. (Approx 2-3 hours). Water cure the treated surface by mist spraying with water 3-4 times daily for 3 days if you wish to hasten the crystal growth. This is helpful on structures that are not intended to hold water. (Eg. Concrete silo bases) In the case of tanks, troughs etc. simply putting some water back in will provide adequate hydration. Even 20 litres of water added to an empty tank with lid replaced will provide a good humid environment to hasten crystal growth.

Tip: On a sunny or hot outside wall, draping a wet bag over your work will help.

SIZE: 4kg

Download the Crystalfix Directions Booklets here.

Customer Reviews

Based on 2 reviews
sheep farmer
fix leaking concrete troughs stop rust stains

Had concrete trough which had cracked where steel reo had rusted and expanded. painted with Mr Crystal, the leak sealed up , the rust stains disappeared and it hasn't got any worse in 10 years. had success every time I use it. Better to use it early before damage gets too bad

M Berry
Outstanding product

This product has actually worked repairing leaks on our concrete water tank. It is a little tricky to get the water in the larger cracks not to wash away the product but once on there it actually has stopped the leaks - would definitely recommend, so much cheaper than replacing the tank. ‚ò∫