A tough, single-pack polyurethane sealer made for protecting concrete-rendered ponds below the waterline. This black version of Prymax Pond Sealer gives a strong, clean finish that's resistant to water, oil, and everyday chemicals. It forms a hard, non-absorbent surface that’s easy to keep clean, helping to reduce maintenance and preserve the look of your pond long-term.

This product should be used specifically below the waterline. For areas above the waterline or any surrounding paving, use Prymax Marine Clear Seal. Beyond pond sealing, it’s also suitable for damp-proofing internal render, plaster and plasterboard, as well as sealing dusty concrete floors. It can be used on internal wood surfaces and externally on walls, but should be overpainted for UV protection.

Key Features:

• One-pack formulation – no mixing needed
• Long-lasting finish with excellent durability
• Water-resistant and chemical-resistant
• Easy to clean and maintain
• Suitable for multiple surfaces indoors and out
• Fast-drying: touch dry in under an hour
• Full chemical resistance after 72 hours
• Can handle light foot traffic after 12 hours

Application requires two coats of clear followed by two coats of black, all within three hours of each other. If that window is missed, allow to cure for 24 hours and lightly sand before recoating.

This black variant gives a professional, dark finish that works well in garden ponds and contemporary landscaping. It’s a practical choice for both new builds and refurbishments.

Aquacadabra acts as credit broker/intermediary and not as a lender.

Klarna's credit products are provided by Klarna Bank AB, which is authorised and regulated by the Swedish Financial Services Authority, with limited supervision by the Financial Conduct Authority. More information can be found here.

Newpay finance options are provided through Deko’s platform by NewDay. P.D. Aquatics Ltd, t/a Aquacadabra is an Introducer Appointed Representative of Pay4Later Ltd, t/a Deko, which is authorised and regulated by the Financial Conduct Authority (ref no 728646) and is a credit broker, not a lender. NewDay Ltd is authorised and regulated by the Financial Conduct Authority (ref no 690292) and is authorised by the Financial Conduct Authority under the Payment Services Regulations 2017 for the provision of payment services (ref no 555318). More information can be found by clicking the newpay option above, or in the Newpay FAQs.

We really want you to be happy with the product that you've received. If however, when the goods arrive they're not what you want, then no problem - we have a 60 day no quibble return guarantee. Just let us know that you're going to return the item(s) by contacting us(stating your Order Number) and complete the returns packing slip that will have been included with your delivery. This will help us to quickly identify the item that you have returned (unopened and unused) - and we'll put a refund through for you.