“Algae thrive with the warm, sunny conditions in summer. Feeding rates are also much higher during the summer and a high organic load will increase the algae problem, so reducing the organic load with frequent water changes is of great benefit.” -Mark Anderson, Vermont Koi and Goldfish
Algae is essential to a healthy pond. Too much algae, though, discolors the water and can be an indicator of poor water quality. Not only is excessive algae unpleasant to look at, but it also can hurt your fish and aquatic plants.
Summer provides the perfect conditions for an algae bloom – excess nutrients in the water, plenty of hours of sunlight, and warm temperatures – so this is the season to be vigilant about algae prevention.
“When your pond turns green, resist the temptation to drain it, scrub it and refill it with fresh water!” –Isa Webb, The Bloomin Bog Water Gardens

When it comes to pond aesthetics, there’s nothing like clear water. Clear water looks great and allows you to see your fish and plants. Using Nualgi will help keep water clear and balanced. If you have a natural pond bottom, consider switching to an artificial surface. You can add the nutrients to the water that a natural bottom supplies, but not get muddy water from fish disturbing the bottom. A good bio-filter will also help keep water crystal clear.
“We have been helping people make their own bio-filters for years,” said Lorraine Gregson of Forest City Pond Club. “We used to have 14 ponds in our yard where we imported, bred and sold Koi. We used the upflow filter system with lava rock 26 years ago, but in some of the ponds I still had hair algae and in others suspended algae. Then a friend of ours found the filter we are using now on the internet and it takes me next to no time to backwash them and I haven’t cleaned the bio-media in about 26 years.”
Outcompete the bad algae
Nualgi is packed full of nutrients that feed diatoms (the good algae you want). This gives the diatoms a boost, so they thrive, out competing nuisance algae. Plus they create the vital oxygen that all the life in your pond needs – including our good bacteria friends that clean that brown sludge.
“I’ve read so many posts in here about UV filters. 2 years ago my pond went green and I tried many remedies. I was going to buy a UV filter, but my pond store told me that should only be the last ditch effort, as the light doesn’t discriminate about what it kills, including beneficial bacteria. They had me try Nualgi, and after about 6 weeks, my pond cleared up, fish were healthy, plants flourished. Haven’t had an algae problem since. Will never use a uv filter” – Tim W, Nualgi Ponds user
ALGAE BLOOMS
An algae bloom is an accelerated and uncontrolled growth of algae in your pond.
As fish become more active in the summer, it is easy to overfeed them. Uneaten food tays in the water releasing extra nutrients, which can throw off the balance in your pond.
“The food fed must be consumed within five minutes and do not throw too much food at the same time,” Ricky Cheng Hoseki Koi and Pond advised. “Do constant water changes depending on your loading and style of feeding.”
Also keep in mind that when the water temperature reaches the 80s fish will become less active, requiring less food.
The most common method of algae control is to add a copper based algaecide to pond water. Algaecideis a useful tool, but use it with a light touch if at all. Overuse of algaecide and/or killing algae off too quickly can come with its own set of problems, including oxygen depletion in the pond and toxic reactions for fish, native plants, and wildlife.
Nualgi’s patented water treatment + super-strength bacteria in Beneficial Bacteria work together to recalibrate your pond chemistry. With a small regular dose of both, you give nature the helping hand she needs to rebalance your pond’s ecosystem. The result? A beautiful crystal clear pond that is a haven to fish and wildlife – and a joy to sit beside.
String algae is made up of long strings, just as its name implies. It attaches itself to plants, hangs from rocks in waterfalls, or hangs on the surface of the water. The long strands of algae get tangled together into thick mats and are able to double their weight within 24 hours.
String algae can contribute to oxygen loss, but otherwise isn’t dangerous to fish. It is unsightly, though. The best way to rid your pond of string algae is to manually remove it and then balance your water chemistry. String algae removal typically takes 20-70 days using Nualgi Ponds in combination with beneficial bacteria.
“High phosphates and organic matter can be reduced with regular water changes, and using Nualgi will control the green water.” -Mark Anderson, Vermont Koi and Goldfish
Your best bet is to prevent excessive algae rather than having to remove it and treat your pond. Don’t overstock fish, don’t overfeed fish, check the levels of nutrients in your pond, and make sure it’s properly aerated.