Piscimar Algiblack +

Piscimar Algiblack+ PM-624 is a concentrated liquid algaecide designed to tackle black, brown and yellow algae in swimming pools – particularly the stubborn kind that clings to walls, floors and grout lines and refuses to shift with standard chlorine treatment. When regular sanitisation isn’t enough, this is the shock treatment that steps in.

Black algae in your pool: how to spot it and get rid of it

Dark patches on pool walls or floors that keep coming back despite repeated chlorine doses are a tell-tale sign of resistant algae. Black and brown algae anchor themselves into porous surfaces and grout, forming a protective layer that ordinary chlorine simply can’t penetrate. Adding more chlorine at that point rarely solves the problem – you need a targeted algaecide.

Piscimar Algiblack+ PM-624 is formulated specifically for these resistant strains – black, brown and yellow algae that have already taken hold. It works as a shock treatment when the problem is visible and needs direct action, not just prevention.

Available in 1.1 kg, 5 kg and 25 kg formats, it suits everything from domestic pools to professional maintenance programmes.

How to apply Piscimar Algiblack+ – dosage and method

For best results, the pool needs to be prepared before you add the product: filtration running, and all affected surfaces thoroughly brushed.

Step-by-step application guide

1. Brush all affected areas before adding any product to the water.
2. Pre-dilute Algiblack+ in a bucket using approximately 9 times the product volume in water. This step is essential given the product’s high concentration.
3. Pour the diluted solution into the pool, distributing it evenly across the water.
4. Keep the filtration system running to circulate the treatment throughout the pool.
5. Brush again after approximately 24 hours to remove loosened residue and assess the result.

Recommended dosage

• Shock treatment: 1.5 L per 100 m³ when algae are visibly present in the pool.
• Weekly maintenance: 0.3 L per 100 m³ once a week after the pool has been recovered, to help prevent regrowth.

What to expect after treating with Piscimar Algiblack+

Within the first 24 hours, algae stains should begin to lose their intensity and lift away from surfaces. After that window, brush the treated areas again to clear loosened debris and get a clear picture of how the treatment has worked.

If patches persist, check three things before repeating: pH balance, phosphate levels, and whether the filtration system has been running long enough. Elevated phosphates in particular can fuel algae regrowth – if levels exceed 100 ppb, treat with a phosphate remover first. Once the pool is clear, the weekly maintenance dose keeps resistant algae from returning.

Why choose Piscimar Algiblack+ for resistant algae

Standard maintenance algaecides are designed for prevention. Piscimar Algiblack+ PM-624 is built for situations where prevention has already failed – where black, brown or yellow algae have embedded themselves into pool surfaces and aren’t responding to routine treatment.

If you’re seeing staining on concrete or gresite surfaces that chlorine alone won’t shift, this is the product to reach for. It can be used as a one-off shock treatment or incorporated into a weekly maintenance schedule once the pool is back under control.

• Targets black, brown and yellow algae in pools.
• Effective where standard chlorine treatment falls short.
• Use as a shock treatment or for ongoing weekly maintenance.
• Available in 1.1 kg, 5 kg and 25 kg sizes.

Use biocides safely. Always read the label and product information before use.

Why buy Piscimar Algiblack+ from Pools&More

Pools&More is an authorised Piscimar distributor and a specialist pool and water treatment retailer. That means you’re buying from a team that understands how these products work in practice – not just what the label says.

With a product like Piscimar Algiblack+ PM-624, getting the application right matters. Resistant algae don’t disappear just because you’ve added the right product – dosage, brushing technique, filtration run time, pH and phosphate levels all play a role. Our team can help you work through each of those steps.

• Authorised Piscimar distributor.
• Specialist pool and water treatment retailer.
• Pre- and post-purchase advice available.
• Support with dosage, application and ongoing water maintenance.
• Help choosing the right treatment for resistant algae in pools.

Frequently asked questions