POND BLOCK
POND BLOCK
Control filamentous algae effectively and effortlessly with Pond Block! This product gradually dissolves in your pond and remains active for months, regardless of rain or evaporation. Ideal for year-round use, even in winter.
BACTA CLEAR + 2x POND BLOCK
- For 2,000 L
- Algae free in 10 days
- Thread algae and floating algae control
BACTA TAB + POND BLOCK
- For 10 to 1,000 L
- Algae free in 10 days
- Thread algae and floating algae control
Combating Thread Algae - Pond Block + 5 Oxygenating Moss Balls Against Algae
- Usage: 1 block per 1,000 L
- In 10 days thread algae free
- Incl. oxygen plants
BACTA CLEAR + 10x POND BLOCK
- For 10,000 L
- Wire algae free in 10 days
- Thread algae and floating algae control
BACTA CLEAR + 5x POND BLOCK
- For 5,000 L
- Wire algae free in 10 days
- Thread algae and floating algae control
Thread Algae Fighting Pond Package - Small
- For 1,000 liters of water
- In 10 days filamentous algae free
- Placement: loose in the water
This is what our customers say!
Excellent 
200+ reviews at 
Marjoke Bakker
Oxygenating plants and a bottle of Bacta clear
Purchased: Pond clear package - M
My pond was quite murky, so after a good conversation with Simon, I decided to follow the advice: more oxygen plants and a bottle of bacteria. I ordered the recommended package, but after four days no improvement was visible. Full of disappointment, I contacted customer service. They advised me to be patient and give the process 2-3 weeks. Although I had my doubts about it, I decided to wait anyway. And what turned out? After two weeks, the water started to clear and I even saw frogs that I had never noticed before! Thanks team vdvelde, and apologies for my impatience!
Patrick Müller
Plants are growing much better now and water is crystal clear
Purchased: POND SUBSTRATE pond substrate - 40 liters
Last year I had a landscaper install a plant filter at my swimming pond, recommending lava and some plants from the local garden center. Unfortunately, things went completely wrong; the plants died one by one and I suffered an algae infestation. After contacting customer service, I was advised to replace the lava with pond substrate and order some more plants. Now, several months later, the plants are growing well, and my filter is finally free of algae.
Fenna Schmidt
My little city pond
Purchased: Complete Pond Package - S - Red
I had been dreaming of having a pond in my urban garden for some time, but it always seemed like such a hassle. Online I found a complete package and decided to take the gamble, although I was skeptical about the quality of plants sent through the mail. But to my surprise, everything was delivered neatly and well-packaged. Within no time I had my pond set up. To my delight, after only two months I saw the first water lily bloom, and as icing on the cake I discovered salamanders in my pond. No idea how they got there, but it only adds to the joy. Truly enjoying it!
Susi Werner
A must for anyone with a pond (large or small)
Purchased: Simons Pond Advice Book
This book completely meets my expectations. A great guide with lots of great tips on pond construction, pond plants and design.
Highly recommended purchase on my part.
Great book!
Jules Chabot
Blue lily: beautiful!
Purchased: Hardy Blue Water Lily - Nymphaea Blue Queen
Thank you very much for the generous delivery of the swamp iris "Blue Lis".
The new plants have been planted and I am curious to see if they will bloom this year.
There is good news about the water lily "Blue Queen": It is also blooming here in blue - and how beautiful!
Bart Timmermans
Removing soil sludge without a vacuum cleaner
Purchased: Soil Dirt Pond Removal Package - M
After years of accumulation by fish, quite a bit of silt had accumulated in my pond.
At first I thought about a pond vacuum cleaner, but after contacting customer service I opted for the bottom debris removal package. I was skeptical, especially because the water became murky the first week. But after a month, the silt has reduced considerably. No hassle with a vacuum cleaner, and great results!
I am a fan.
Johanna Brink
water lilies for more biodiversity
As lovers of greenery, we were looking for a sustainable addition to our project. Van der Velde's water lilies were a hit! With DROP & GROW, it was really simple: plant and enjoy. We asked for different varieties and this was no problem either. Delivery was perfect. Within a week we already saw leaves above water, and meanwhile there are several flowers blooming. Both we and our customer are very enthusiastic.
Raphael Blanchard
Oxygen plants save my fish
Purchased: Oxygen Plants Pond Package - L
My fish were gasping for air, so I was looking for an air pump. Then I read that oxygen plants could also solve this problem. I ordered the package that fit my pond, and now my fish are swimming around carefree again. Additional plus: my pond water is much clearer. Fish happy, me happy!
Greta Schultze
Very happy with my small pond
Purchased: Complete Pond Package - XS
This handy kit helped me set up my mini pond quickly. Everything you need is included! The service and advice were top notch, much better than at the garden center where no one really knows anything.
Maria Maes
From maintenance to an organic swimming pond
Purchased: Complete Plant Filter Package - L
I was tired of constantly cleaning the pump, so I decided to convert my pond to an organic swimming pond. With the plant filter package from vdvelde.com, it worked out perfectly! Now I enjoy a beautiful, natural filter and lovely swimming water.
Frequently asked questions about Pond Block
Pond Block dissolves. Important: Dose Pond Block as indicated on the package, otherwise it may cause damage to your pond plants. In fact, Pond Block can be overdosed and cause damage to plants.
Pond Block does not increase water hardness. It is designed to control algae by releasing substances that destroy algae, but it does not contain calcium or magnesium, so it does not affect water hardness.
BACTA CLEAR can increase water hardness. Here it is important that the pond is arranged correctly, because then algae are prevented year round. You can set up the pond correctly by placing a layer of porous pond substrate on the bottom and by adding sufficient and different types of plants to the pond.
The bacteria, substrate and different types of plants work together to prevent pond problems and keep the pond balanced year-round.
How this works and how to tackle it can be found step by step in our pond check.
Pond Block is a useful tool to quickly get rid of your thread algae, floating algae or other type of algae but it is only a temporary solution.
If the pond is set up improperly, algae will return again. To prevent this, it is important that the pond be set up correctly. A 5-10 cm layer of porous pond substrate on the pond floor is essential for this. In addition, sufficient and different types of aquatic plants must be present, such as marsh plants, oxygen plants and water lilies. These constituents work together to keep the pond healthy and clear year-round.
A good balance between these elements is crucial for a healthy pond. Each aspect reinforces the other, and only by using them together can you achieve the desired results. You can read exactly how to do this step by step on our pond check page: pond check.
Yes, Pond Block is safe for both pond plants and fish when dosed correctly. It is important to stick to the recommended dosage: use one Pond Block per 1,000 liters of pond water. This will keep the pond balanced without damage to plants or fish.
Pond Block takes about two weeks to be effective and remove algae. Additional doses are not necessary; algae will disappear on its own within this period.
To prevent algae from returning in the future, a properly designed pond is essential. Provide a layer of substrate on the bottom, plenty of aquatic and oxygen plants, and add pond bacteria twice a year.
Want to check that your pond is set up properly to prevent algae formation? Then go through our handy pond check.
Pond Block can be overdosed, this is not good for the plants and animals in your pond. If you have a pond of, say, 250L or 500L, add a quarter or half of the Pond Block to the water. What remains can be kept and reused later.
Pond Block is added as soon as the algae return. So Pond Block is really only a temporary solution against algae.
Want a long-term and natural solution against algae so your pond stays healthy and clear year-round? Then make sure you set up your pond correctly.
You do this by placing a layer of porous pond substrate on the bottom, adding sufficient and different types of aquatic plants and by adding bacteria of BACTA CLEAR to the water 2x a year.
Want to read step by step how to do this? Check out our pond check.