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Supa Pond Blocks

Slow-release pond blocks that hold algae back rather than clearing it once it's bloomed

£3.65

How often?

£3.65same price, however often you have it

· tracked · UK mainland estimate · 14-day promise

UK delivery £2.99 · free over £39

Secure checkout by Stripe · Card, Apple Pay & Klarna

What the makers don't tell us

There's no published block count per pack, no pond-volume dosing rate and no stated lifespan once it's dissolving, so working out how many you need for your size of pond is a judgement call rather than something you can read off a chart.

Secure checkout

Tracked delivery

Easy returns

Why we chose it

Algae prevention only works if people buy it before the pond's already green, which is a hard sell but a genuine one. It's a small, cheap line that's easy to mention to anyone buying pond stock in spring.

— Matt, founder

Specifications

Brand: Supa

Full description

Green pond water is not usually a sign anything has gone wrong. It's what stagnant, nutrient-rich water does on its own if nobody intervenes, and by the time it has turned the colour of pea soup there is already a lot of algae to shift.

This block works ahead of that point rather than after it. It sits in the water and slowly dissolves, releasing di-methyl urea as it goes, which inhibits the growth of waterborne algae. Supa describe it as totally harmless to fish and healthy pond plants, and recommend putting one in early in spring, before the growing season gives algae the chance to get established.

Slow-dissolving treatment block for garden ponds
Active ingredient is di-methyl urea
Works by inhibiting algae growth, not by killing an existing bloom
Described by Supa as totally harmless to fish and healthy pond plants
Best introduced early in spring, ahead of the growing season

What the makers don't tell us. There's no published block count per pack, no pond-volume dosing rate and no stated lifespan once it's dissolving, so working out how many you need for your size of pond is a judgement call rather than something you can read off a chart.

Who it's for: pond owners who'd rather stop algae building up than deal with it once the water's already green, and who are prepared to treat early rather than reactively.

Delivery

Tracked UK delivery — your estimated arrival date is shown above and updates automatically. Standard delivery £2.99, and free on orders over £39. Full details on our delivery information page. Delivery information

Returns

14 days to change your mind, no interrogation. Items need to be unused (sensory products unopened, for hygiene). Full details on our delivery & returns page.

Payment

Secure checkout by Stripe — cards, Apple Pay, Link and Klarna. We never see or store your card details.

Common questions

What does this block actually do to the pond?

It slowly dissolves in the water, releasing di-methyl urea, which inhibits the growth of waterborne algae rather than removing algae that's already there.

Is it safe with fish and pond plants in the water?

Supa describe it as totally harmless to fish and healthy pond plants.

When's the best time to use it?

Early spring, before the growing season gives algae the chance to build up - Supa's own guidance is to get ahead of it rather than treat it once it's bloomed.

How many blocks does one pond need?

The makers don't publish a dosing rate against pond size, so this isn't something we can answer from the card - it's a case of judging it against how your pond responds.

How long does delivery take?

Your estimated delivery date is shown above and updates automatically. UK orders are sent tracked — standard delivery is £2.99, and free on orders over £39.

How do I track my order?

As soon as your order is dispatched we email you a tracking link, so you can follow it all the way to your door.

What if I need to return my order?

You have 14 days from delivery to change your mind. Just email us with your order number and we’ll send the return steps the same working day — see our delivery & returns page for details.

Why buy from Giddy Pets?

Carefully selected by pet ownersEvery product is chosen and quality-checked by people who actually live with dogs, cats and small pets.
Tracked delivery on every orderUK delivery with tracking as standard — and it’s free when you spend over £39.
UK customer supportReal, UK-based humans read every email — usually Matt, the founder. No bots, no ticket numbers.
Easy returns14 days to change your mind, no interrogation. If it’s not right, we’ll make it right.