Desjoyaux poolsShock Chlorine Granules 5kg – Stabilised, Fast-Dissolving Hot Tub Chemicals & Swimming Pool Treatment – Kills Bacteria, Rapid-Action Water Sanitiser for Pools, Spas & Jacuzzis

I have a 4000L pool and over the last two weeks struggled with greenish water. I had put more chlorine tablets, added liquid algaecide and vacuumed a few times, but achieved little and the water remained cloudy and green.I diluted 80 grs of these granules in a jar and poured it by the outlet. Within SECONDS the areas next to the inlet and outlet had turned clear !After 3 hours the whole pool is a nice clear blue colour. Not a trace of greenish stuff, I don't even need to vacuum the floor and walls. The water looks like it did the very first day.Brilliant stuff which will last for ages.

Arrived on time did what I needed

Excellent, did exactly what it said, but came with no instructions, hence the 4 stars, otherwise it would have 5.

We have a 10ft Bestway max steel pro pool. A little visitor recently asked why the pool was green. Good question. Wed been using one of those little floating chlorine dispensers with the tablets, but after a little tea search, it appeared this stuff was effective in dealing with the algae. And it is! Annoyingly, I didn’t take before and after pictures, but I measured out 60g (a tiny fraction of the amount in the box, making the >£50 price decent value) mixed it in a measuring jug and fired it into the pool next to the inlet pipe. I did that in the evening and by the next morning the pool was clear. I was both surprised and delighted. So we’ll be using this once a week from here on in. Note - we also bought a pool vacuum (to address the detritus on the bottom) but haven’t used that yet.

Bought for hot tub. It'll last until I die as there's a lot. Perhaps better suited for a pool.Measurements for dosage is in m3, so I searched online to convert for my 1000L tub. Which held basically 1 m3 to the line. I'd have loved calculations for literage

We had a 12foot pool which went cloudy & had creepy creatures starting to appear...eeek!!!Friend recommended this & worked a treat!Clear water & no creatures!We bought a pool vacuum & bigger filter which helped too, best to get over sized pump for pool.

No dosage instructions to 'shock' the pool, just daily maintenence instructions which is fine if that's what you are using it for. I am a novice, so would have liked the dose for shocking the pool, which is what I purchased it for because it is advertised as shock.

These are just regular chlorine granules, not just for shock treatment, so buy with confidence. For a small pool like mine, this is brilliant value, so much better than the 500g or 1kg containers, which are much more expensive this year for some reason.