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With the longer daylight hours and warmer temperatures, summertime brings the outdoors to life. Now is the time to be making sure the pond is prepared for all that summer brings, and to ensure health and vitality in your fish, plants and wildlife.


There is plenty of preparation needed for ponds to thrive during the summer months. A good maintenance routine will help prevent water quality issues and health related problems in your fish.


Summer maintenance


Water quality issues after winter


After a long winter with not much activity, the pond may begin to spring to life without much interference. One of the most important things to check early and regularly in the season is the water chemistry of the pond. Sludge at the bottom of the pond can reduce pH to dangerous levels and provide a breeding ground for disease-causing organisms to hide. If physical removal isn’t an option, regular dosing of Pond - Sludge Remover will digest sludge using a blend of enzymes and bacteria.


Heavy rainfall throughout the winter and spring can reduce hardness levels in the pond. This is due to a lack of minerals present in rainwater (this is also why it is not recommended to use a water-butt in the pond). Without minerals (hardness), dangerous fluctuations and crashes in the pH can occur. A sudden pH crash (acidification) of the pond will generally kill most livestock. To restore adequate hardness and a safe pH after heavy rainfall, use Koi Care - KH Buffer Up. In some areas, the local tap water contains significant mineral content, and so a partial water change may be all that is required. Use Pond - Tap Water Chlorine Remover for any new tap water added to the pond to remove harmful chlorine, chloramine and heavy metals found in tap water.


Ammonia and nitrite levels are also often found to be higher this time of year. This usually occurs once the fish begin feeding again, before the bacterial colonies in the filter have re-established after winter. Adding cultured bacteria into the filter early on will help prevent any sudden ammonia or nitrite spikes. NT Labs offer two liquid filter bacteria formulations: Pond - Live Filter Bacteria for ornamental fish ponds or Koi Care - Filter Bugs for koi ponds. Both can be added regularly throughout the season to help maintain healthy bacteria numbers in pond filters, or to re-establish the filter after adding a strong medication. These products can also be safely double dosed at the start of the season. If ammonia is already present in the water, chemical filtration will reduce it quicker than biologically. Pond - Ammonia Remover or Koi Care - Zeolite is a natural rock that will absorb ammonia from the water. Removing ammonia will also reduce nitrite and nitrate. When using zeolite, it is important to test for ammonia as the rock has a finite absorption capacity. Koi Care - Zeolite also includes recharging instructions on how to regain absorption capacity. It is still recommended, however, to replace 50% each time it is recharged as it never regains total capacity.


Filter Maintenance

Many pond filters rely on layers of foam to act as both mechanical and biological filtration. Foam needs manual cleaning to remove trapped dirt but without killing off the bacteria inside. To clean filter foams, use a bucket of water from the pond itself or untreated rainwater. Do not use tap water near filter foams as any chlorine and chloramine present will kill off the biological filtration. Many pond keepers believe having thoroughly clean filter foams is ideal. They are unaware of the duality foam possesses in also growing the bacteria that performs the nitrogen cycle. Over time foam loses its efficiency and will need replacing. Most filters contain multiple layers of foam or different media for growing bacteria. It's recommended to change the media in stages to prevent complete removal of biological filtration.


Green water issues

A common maintenance task that is too often left until it is too late is the changing of the UV clarifier bulbs. These ultraviolet bulbs need changing every spring before the sun gets too much of a chance to shine. Once summer arrives, the sun will proliferate free floating, single-cell algae until the clarity of the pond is lost to a pea-green soup effect.


Installing a fresh UV lamp will combat green water over time. To quickly resolve a green or cloudy pond, use Pond - Clears Green & Cloudy Water. This flocculating treatment will clump small algae or dirt particles, causing them to sink to the bottom of the pond. If the pond is filtered, these larger dirt clumps will then be trapped in the filter sponges. In an unfiltered pond, use a sludge remover treatment. Some precautions need to be observed when using Magiclear. Ensure adequate oxygenation of the water, a minimum carbonate hardness level of 6 dKH and a pH above 7.0. If the pond is very green, it is recommended to change 50% of the water before treating. This will help prevent severe oxygen depletion that could occur when using the treatment to combat green water algae.

Adequate oxygenation


As temperatures increase, saturated oxygen levels in water depletes. Water rarely exceeds 10ppm dissolved oxygen, whereas atmospheric air contains on average 200,000ppm. It is important to increase and maintain adequate surface agitation to allow as much oxygen into the pond as possible. Fountains, waterfalls and air pumps all help in keeping oxygen levels high during the summer months and these should be running 24 hours a day. A muggy, stormy night will reduce atmospheric oxygen levels. Plants (and algae) absorb oxygen at night (reverse photosynthesis), contributing to hypoxic conditions. Many pond keepers wake up to a pond full of dead fish because they turn off their ‘noisy’ pond at night.


Changing temperatures alters feeding habits


With the rising temperatures of summer, pond fish find their metabolisms increasing too. A higher metabolism will stimulate their appetite, so their diet should be modified to cater for their changing needs.


Temperatures above 12°C


Medikoi Staple with Colour Enhancer, Medikoi Health and Medikoi Growth are all suitable to feed in the summer months. Their differences have been discussed in greater detail in a previous article “A guide to feeding your pond fish with Medikoi foods!”


Medikoi Staple with Colour Enhancer contains spirulina for natural vibrant colour enhancement. Medikoi Health contains propolis, a natural antimicrobial to aid fish recovery after infection and Stimmune to support the fish’s immune systems. Medikoi Growth has a higher percentage of protein (40%) for rapid growth rate. A combination of all 3 will provide your pond fish with a complete diet that supports colour, growth and vitality. For the ultimate in fish nutrition, Medikoi Probiotic contains specialist gut bacteria and prebiotic ingredients that will enhance absorption and breakdown of waste.


Temperatures above 14°C


Once the temperature climbs above this threshold, there is one more Medikoi food that can be fed for premier growth and health. Medikoi Probiotic Growth has an extra 27% protein content compared to Medikoi Growth (51% vs 40%). Medikoi Probiotic Growth will provide koi with the ultimate in balanced growth, colour, shape and definition.


When feeding foods that contain high amounts of protein, many pond keepers find a buildup of white froth on the water surface. This is not usually harmful but can be very unsightly. If the problem persists, use Pond - Foam Control to safely breakdown the froth. Removing this foam will increase gaseous exchange and maintain the correct pH.


Adding fish to the pond


A trip to your local specialist aquatics retailer to add new fish to your pond should always be a pleasurable and enjoyable experience. Whether it’s a small selection of goldfish or gigantic koi carp, care should be taken to ensure the fish you’ve chosen are of good condition.


Healthy livestock - what to look out for

Any reputable aquatic store will have plenty of quality livestock for sale. It is important to ensure that the fish offered are healthy and in good condition.


Look out for any of the following to avoid purchasing ill fish:

  • Listless / Diseased fish - look out for any fish with obvious diseases - white spot, fungus, tail or fin rot. Fish that are not swimming with the others is often a sign of illness.
  • Emaciated / Skinny fish - a fish that has been deprived of food will have a weakened immune system, making it more susceptible to disease.
  • Dirty enclosures - a dirty enclosure would suggest a lack of upkeep and care of duty towards the livestock. Many pathogens thrive in dirty conditions and the water quality may also be less than ideal.

Once the new fish have been chosen and taken home, it’s important to introduce them safely to their new environment.

  • Temperature acclimatisation: Float the fish bag on the surface of the pond for 20 minutes to allow for the water temperature inside the bag to equalise to the ponds temperature. More often than not, this will be a cooling process as fish bags usually warm up during transport.
  • Equilibrium of water parameters: After the initial floating period, open the bag and roll down the sides to create a floating ring. Slowly add water into the bag over the next 20-30 minutes. This will mix the pond water with the transport water and allow the fish to adjust to any differing water parameters gradually.

In exceptionally hot conditions, many aquatic stores will add oxygen to the fish bag before transport. Once the fish bag has been opened at home, it is advisable to acclimatise the fish faster than recommended to prevent oxygen depletion in the bag.


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