Home > FAQs > FAQ: Pond Water Problems

FAQ: Pond Water Problems

By: Dr Gareth Evans - Updated: 31 Mar 2020 | comments*Discuss
 
Water Ponds Algae Water Quality Hardness

Keeping the water in good condition is an absolutely essential part of maintaining a healthy pond, but sometimes it can seem to be one of those things which is easier said than done!

Fortunately, however, most of the water problems that do occur in garden ponds can usually be fixed, and often, thankfully, without too much of a carry-on.

Here’s our own “top ten” of frequently asked questions about water quality and related issues.

It’s surprising how often the same concerns and queries keep cropping up, so if you have a problem in your pond, there’s a good chance you should find the answer to it amongst them.

1. Why’s My Pond Water Gone Green?

The simple answer is that it’s full of unicellular algae. It tends to be a problem for newly constructed ponds, but older ones can also suffer, especially in the spring as the days lengthen and the sun begins to shine more.

It’s principally due to an excess of nutrients – chiefly nitrates – in the water, which give these single-celled plants a head start and allow them to grow and multiply quickly. Cutting back on the amount of dead plant material in the pond, clearing out any fallen leaves and not over-feeding the fish often makes all the difference.

2. What Is Water Maturation?

Before you plant any new pond – and long before you think about introducing any fish – the water needs to mature. It simply means allowing it to settle and turn from being tap-water full of chlorine and chemicals into a more natural pond water. The process is also sometimes known as “conditioning”.

3. What Is Hard/Soft Water?

Whether water is considered “hard” or “soft” depends on the levels of dissolved calcium it contains – the more calcium, the harder the water. Rainwater naturally contains none, but it picks it up as it flows over rock and through soil so the geology of your local area influences the softness or hardness of the water supplied.

As a rough guide, the water in Scotland, most of Wales and Cornwall tends to be soft, while in the Midlands it is hard and very hard throughout most of the rest of England – though individual areas do vary. It can be important for the pond keeper because some plants and pond animals have particular needs and also because it can sometimes also affect aspects of the water chemistry too.

4. What Is pH And Why Is It Important?

It is the measure of the acidity or alkalinity of the water – and strictly speaking it relates to the hydrogen ions present. A pH of about 7 is “neutral”; the higher the number the more alkaline the water and the lower the pH, the more acidic it is.

Most pond-life prefers water around neutral, although some favour slightly acidic or slightly alkaline conditions; again pH can affect water chemistry, so it’s an important factor in overall water quality.

5. How Can I Control Blanket Weed Algae?

Options for controlling blanket weed include dosing with barley straw – an old traditional and surprisingly effective method, algaecides, nutrient removers and a range of electronic devices which use electrical discharges or ultrasonic waves to break up the algal strands.

6. Why Are My Fish Gasping For Air In The Summer?

Warm water naturally holds less oxygen than cold, so the rise in temperature at a time when the fish are active and feeding the most will tend to expose any problems in water aeration. Poor oxygenation can be caused by a broken or blocked pump, the sudden onset of the dreaded “green water”, the arrival of excess nutrients in the water, evaporation or simply too many fish. The only cure is to determine the underlying cause and deal with it – quickly!.

7. What Are The Key Factors For Water Quality?

The key factors are: pH, dissolved oxygen, ammonia, nitrite, nitrate, carbonate and calcium levels (hardness).

8. How Can I Stay On Top Of Water Quality?

The only way is by routine testing. A good testing regime can often allow you to spot problems as they develop and deal with them long before they become a serious threat to the well-being of your pond. Regular testing is essential for new ponds, but even for established ones, fortnightly testing will help you keep an eye on what’s going on.

9. Why Are Leaves/Grass Clippings Such A Problem?

Too much plant material in the pond fuels bacterial growth as the microbes break down the leaves or grass. All this activity by these bugs uses up a great deal of the water’s dissolved oxygen while also adding excess nutrients to the pond, which in turn encourages algae.

10. Can I Get A Water Treatment For.............?

Water treatments are very big business and a huge range are available to deal with most of the common pond ills. As well as barley straw and algaecides there are buffers to regulate pH, de-chlorinators to remove the chlorine from tap-water, anti-foaming agents, “sludge busting” treatments, specialist pond fertilisers and a whole variety of medications for fish disease.

Water quality is, obviously, vital for the aquatic environment – especially if the pond contains fish; according to some estimates, it can account for as much as 90 per cent of all their health and husbandry problems. It really is small wonder that so many of us are preoccupied with ensuring that our own pond-water stays in good order.

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
[Add a Comment]
I have a problem with our pond which has a flow of water through it. The water comes from field run off and goes through our pond and into the local burn. There are green balls growing in copious quantities. They come to the surface with sunlight and/or warmth and sink at night. They are jelly like. I remove anything up to 5 buckets a day and these dry up white in a sheet after about 3-4 days if dry. I do have photos. Can anyone advise how to eradicate these jelly balls. We have not stocked pond which is about 75m x 10m but there are frogs etc in there.
stuatel - 31-Mar-20 @ 2:10 PM
Mu - Your Question:
My son gave my pond a much needed clean. Fish were transferred to a large pool in half & half tap & pond water. On clearing large amount of sludge on bottom of pond & removing various items that had fallen he mistakenly removed the concrete slabs which had been laid on liner when it was renewed. Result was , as we understand it , the liner floated up pushing water through overflow and water levels dropped dramatically with the fish now back in it. Had to rescue fish by topping up with tap water. Have lost 5 small & 1 large fish , and the water seems dusty with the filter containing lot of dusty muck. Have had to switch off pump & filter as it was.churning up debris I do have oxygen line going in. The pond has a 2 ft concrete surround which in places is loose & needs repair because of water overflow. The pond is filled now totally with tap water and level is stable but need advice.what to do to about making the water suitable for fish.how do I get rid of debris which is pumping through filter when I switch it on.

Our Response:
Because of the heat and the need for repair, you may be better advsied to ask at your local aquatic centre for help.
PondExpert - 4-Jul-18 @ 10:59 AM
My son gave my pond a much needed clean . Fish were transferred to a large pool in half & half tap & pond water . On clearing large amount of sludge on bottom of pond & removing various items that had fallen he mistakenly removed the concrete slabs which had been laid on liner when it was renewed . Result was , as we understand it , the liner floated up pushing water through overflow and water levels dropped dramatically with the fish now back in it.Had to rescue fish by topping up with tap water . Have lost 5 small & 1 large fish ,and the water seems dusty with the filter containing lot of dusty muck .Have had to switch off pump & filter as it was.churning up debris I do have oxygen line going in . . The pond has a 2 ft concrete surround which in places is loose & needs repair because of water overflow .The pond is filled now totally with tap water and level is stablebut need advice .....what to do to about making the water suitable for fish ....how do I get rid of debris which is pumping through filter when I switch it on .
Mu - 3-Jul-18 @ 12:07 AM
I had a leak in my waterfall. Unfortunatly this has washed some of the earth into the pond from the rockerary. This in turn made the water cloudy with mud. Is there anything like Sludge Buster that will help to clear the water. I have now repaired the leak!!!!!
Del - 22-Jun-18 @ 12:41 PM
Hi I have got a problem with my pond water. In May I completely emptied my pond after loosing my fish. The water readings were as follows 6.0 acidic nitrite and nitrate were both 0 but the ammonia was between 1.0 ppm and 2.0 ppm. I refilled my pond with tap water and left it for 1 month with the pond filter running non stop. I tested my water todayand to my surprise found that the ammonia level had risen to between 2.0 and 4.0 ppm can anyone explain why, and what can I do to resolve the problem. Regards Stan
stan - 4-Jun-18 @ 5:09 PM
Within the last 3-4 weeks my pond has significantly taken a turn for the worse. It has developed a very thin film on top (although not oily to the touch), & pinky purple stringy droplets have started forming on the oxygenating plants (which look like they have started to die - disintegrating to the touch) & on the liner of the pond (& getting worse by the day). It is a good sized garden pond (about 6 metres by 2 metres) & still has good wildlife (tadpoles, newts, dragonfly nymphs & pond snails all seem to be thriving), but I am very worried that things will slowly start to die off. I have seen dogs & sheep both go in my pond & wonder if anything has transferred off their coats? I have ordered a pond testing kit to check pH etc, but would be extremely grateful for any advice. Many thanks
Crazy Ferret Woman - 29-Apr-18 @ 7:50 PM
@Perere. Sorry, we try to avoid mentioning specific product names if we can. There are many good PH meters out there, try looking for those that have been reviewed and given 5 stars.
PondExpert - 7-Jan-15 @ 11:15 AM
What is the best PH Pond Water Meter or Reader to buy pls.
Perere - 4-Jan-15 @ 2:12 PM
Share Your Story, Join the Discussion or Seek Advice...
Title:
(never shown)
Firstname:
(never shown)
Surname:
(never shown)
Email:
(never shown)
Nickname:
(shown)
Comment:
Validate:
Enter word:
Latest Comments
  • Nana
    Re: Managing Plant Overgrowth Within Your Pond
    I have an average size wildlife pond in my garden full of goldfish and newts, sadly no frogs this year! It is…
    8 April 2020
  • Wanna C
    Re: Repairing Your Pond
    Hi. I have inherited two fish ponds which are raised to about 4 feet and cladded with wood. Both are made from a rigid fibre glass and are…
    7 April 2020
  • Pondnewbie
    Re: Repairing Your Pond
    We've just moved and have inherited a rectangular brick pond approx 6x4 in very poor condition. Apart from massive moss overgrow, there is…
    2 April 2020
  • Donita Gower
    Re: Dealing with Green Pond Water
    We have an old pond which is purely used for wild life.... there are no fish i it. This year the pond water has turned into green…
    1 April 2020
  • stuatel
    Re: FAQ: Pond Water Problems
    I have a problem with our pond which has a flow of water through it. The water comes from field run off and goes through our pond and…
    31 March 2020
  • LondonSteve
    Re: Plants for a Small Garden Pond
    I am building a pond/water feature for a couple of goldfish. It’s a round bowl shape 120cm diameter and 60cm at the middle…
    28 March 2020
  • Log
    Re: Building a Concrete Pond
    What paint do I need to put on the concrete to seal the wall and the base please Peter
    21 March 2020
  • Shazzy
    Re: Your Top Pond Questions Answered
    I have just built a raised pond which is about a foot above the ground. I would love to have frogs and toads in the pond…
    4 March 2020
  • Dons
    Re: What Could be the Reason for all the Fish Dying?
    Lost a fish 2 weeks ago now and just looked in pond 2 more dying they no spots on them
    13 February 2020
  • dieterlost
    Re: What Could be the Reason for all the Fish Dying?
    Hi just changed the water 2/3rds of the pond this January because fish were gasping for air and I’m…
    13 February 2020