Videos

If you’ve noticed your pond going green or murky, your filters could be to blame. Over time, they collect fish waste, leaves, and other debris, which builds up into sludge. This slows water flow and stops your filter from working properly. How a Pond Filter Works Your pump pulls water from the pond through a pipe into the filter box. Normally, this would pass through a UV bulb, which kills microscopic algae and helps keep the water clear. From there, water flows into the filter chambers: Coarse media – traps big debris like leaves and twigs Medium media – catches smaller particles Fine media – removes dirt, sludge, and algae Bio media – plastic pieces with nooks and crannies where beneficial bacteria live By the time water passes through all these stages, it should be clean and ready to flow back into the pond. But if the media get clogged, dirty water can bypass the filters and flow straight back out. Cleaning Your Filter Switch off the pump – never clean while water is still flowing. Remove the filter media, starting with the bio media, then fine, medium, and coarse. Rinse the media thoroughly to remove sludge and debris. (Don’t pour the dirty water back into the pond — instead, use it on your garden beds or lawn. It’s nutrient-rich!) Once clean, replace the media in the order: fine, medium, coarse. Turn the pump back on. Keep Beneficial Bacteria Cleaning removes not just debris, but also some of the good bacteria your pond needs. That’s why we recommend using Envii Filter Feed after cleaning — it replenishes beneficial bacteria that break down sludge, ammonia, and nitrites, keeping both your filter and pond clear. How Often to Clean We suggest cleaning your filter weekly. In autumn, you may need to clean more often because of falling leaves. In summer, fish produce more waste, so filters can clog faster too. If you find your filter isn’t getting too dirty, you can reduce how often you clean it. The Benefits Regular filter cleaning: Keeps pond water crystal clear Reduces sludge build-up Improves oxygen levels Keeps fish healthy Maximises the effectiveness of pond treatments It only takes a short time, but keeping on top of your filter maintenance makes a massive difference to your pond’s health and appearance.

When it comes to pond care, there’s one issue that often flies under the radar: nitrates. At Envii, we think it’s time that changed. In this guide, we’re going to explain what nitrates are, how they get into your pond, and most importantly—how to reduce them naturally. What Are Nitrates? Nitrates are the final stage in the nitrogen cycle—a natural process that happens in every pond. Here’s how it works: Fish waste, uneaten food, and leaves break down into ammonia Ammonia becomes nitrites Nitrites convert into nitrates Nitrates themselves aren’t toxic in small amounts, but too much leads to green water, blanketweed, and stressed fish. Where Do Nitrates Come From? Several everyday sources can increase nitrate levels in your pond: Sludge buildup from decaying organic matter Runoff from fertilisers used on nearby grass, plants or trees Tap water used in water changes (which often contains nitrates) Overfeeding fish, leading to excess waste All of these add up over time—and without enough beneficial bacteria, nitrates can get out of control. How Do Nitrates Affect Your Pond? High nitrate levels fuel the growth of string algae and green water. If you’re battling algae, there’s a good chance nitrates are to blame. Even treatments like Algae Klear Extra (which breaks down algae) can release more nitrates into the water. That’s why it’s crucial to test your water regularly using pond test strips that detect nitrates, nitrites, and pH. Testing for Nitrates We recommend weekly water tests. It only takes a few seconds: Dip the strip into the water Wait 30 seconds Compare the colours to the chart In our recent test, we found our pond water had zero nitrates, with a healthy pH of 7.4—exactly where we want it. How to Reduce Nitrates Naturally You don’t need expensive gear—just smart pond care. Here are our top natural ways to reduce nitrate levels: 1. Control Sludge Use a pond net to remove leaves in autumn and winter A small amount of sludge is fine—it feeds plants But excess sludge = more nitrates 2. Avoid Overfeeding Fish If fish leave food behind, you’re feeding too much Fish (even goldfish!) can find natural food in the pond Less food = less waste = less nitrate 3. Add Plants That Absorb Nitrates Watercress (a bit of a rogue option, but powerful) Oxygenating plants, like hornwort or elodea Submerged plants absorb nitrates all day, every day 4. Tolerate a Little Algae & Duckweed Not all algae is bad—it feeds on nitrates Duckweed can shade the pond, reducing algae growth It’s not always pretty, but it can help balance your ecosystem 5. Careful Water Changes Only change 10–20% at a time Always dechlorinate tap water before adding it Test your tap water—if it contains nitrates, it could make things worse What If You Still Have Nitrates? Then it’s time to bring in the big guns. We use and recommend Envii Nitrate Klear—our natural nitrate treatment. It’s packed with selected strains of beneficial bacteria that digest nitrates quickly and safely. Completely natural  Safe for fish and wildlife Effective and fast If you’re earlier in the nitrogen cycle (dealing with ammonia or nitrites), our product Filter Feed is a better fit. But once you’re in the nitrate stage—Nitrate Klear is your best bet. Final Thoughts Nitrates might be invisible, but their effects are not. If you want a clear, healthy pond—test often, plant smart, feed sparingly, and treat when needed. Got questions or want to share your experience? Drop a comment or contact our support team—we’re always happy to help.

Looking to plant up a small wildlife pond? 🐸 In this video, we walk you through 5 perfect aquatic plants that support frogs, bees, butterflies, and more — all while adding structure and seasonal interest to your pond.

Calculating your pond volume can sound complex but it doesn't have to be. In this video, Ash walks us through the step-by-step process of measuring your pond and the key things to remember when doing so. We even cover how to calculate the volume of irregular shaped ponds. 

Looking to prepare your pond for Summer but don't know where to start? Look no further than this beginner's guide.

It's easy to forget about your pond at this time of year. It's cold, wet and, understandably, the pond doesn't get much attention until Spring. However, the end of Autumn into Winter is an excellent time to carry out a few key jobs that will set up your pond for crystal clear water in Spring.

In this comprehensive video, we dive into everything you need to know about managing duckweed (Lemnoideae) in your ponds effectively.

In this video, we explain everything you need to know about pond sludge, including how to remove pond sludge and how to prevent pond sludge from building up again.

In this video, we visit a beautiful local lake to discuss the problems a lot of lake or large pond owners face. Lakes are notorious for producing large amounts of duckweed, blanket weed, algae blooms and even green water. Ash explains exactly why this is and how to control the levels of these so that they don’t take over your lake or large pond entirely.

In this video, Ash explains everything you need to know about how to clear and prevent green water in ponds. If you're tired of looking at murky, green water and want to enjoy a crystal-clear pond, you've come to the right place.

Caring for a pond can be overwhelming, especially if you’re a beginner. In this video, Ash covers the 5 steps we recommend to anyone struggling with green water, algae, blanket weed or a generally unhealthy pond.

Monitoring the pH, Nitrates and other parameters - ensure your pond is kept in top condition with our complete guide to pond parameters.