Why It's Not Always A Good Idea To Test Your Pond Water

I received this email request for help today and it is like many I get ... with Spring rapidly approaching I thought I must immediately share my strongly held views on water testing with my readers. Everyone will be testing their water soon and I believe they should NOT in the vast majority of cases.

Here is the readers email ....."Recently we cleaned out our 300 gal pond, and added the stuff that makes the water blue to prevent algae. After about 2 weeks, I came home to find my goldfish in serious distress. I tested the water and found the pH was so high it wasn't on the chart. I made fresh water in a container to temporarily house the suffering fish, only to discover my tap water pH is just as high. I have an inside aquarium I transferred the fish to, 5 of the 10 died. It's been 3 days and I can't get the pH down in the pond. I have tried vinegar and a chemical from the pet store to lower the pH. It is a vinyl lined free form, with a filter and a fountain on it. Oh and the stuff to prevent algae? Didn't work. Any ideas?"

The changes made above were done with the very best of intentions ... they just caused more problems.

First of all the reason for adding a blue dye to water is to reduce the absorption of light to slow down the growth of algae. Pond algae are aquatic plants, albeit very tiny ones. They grow and multiply like all plants through the absorption of food nutrients and absorption of sunlight to allow the photosynthesis process to proceed.

My plain simple message ... do NOT add anything to your pond unless you know WHY and WHAT BENEFIT you will get. Rarely does adding anything to a pond help the pond water or the fish. Pond algae cannot be controlled permanently by adding chemicals or dyes  ... do not believe the sales talk or what it says on the bottle without a full understanding.

By the way long after writing this article I discovered a product that does work in removing algae and blanket weed ... click the link to read all about it

Even when the chemicals seem to work they become exhausted and more of the chemical has to be added the following week. Pond chemicals are sold to make money for the manufacturer and retailer .. they are NOT sold to help pond keepers.

I know this sounds cynical but in 99% of cases there is absolutely no need whatsoever for any of these chemicals ... I know I used to sell them. Here I am talking about water conditioners, chlorine removers, ammonia removers and on the list goes.

Coming back to the email I received .... It is almost certain from what is described that the test kit used for testing pH was not working or the method was not being followed in the correct manner possibly.

But there is a much bigger point ... the reader possibly took action based upon an incorrect result and this created more problems ... putting stressed fish into fresh tap water with no air is going to stress the fish even more. What these fish needed more than anything else at the stage of stress was oxygen (air) and a partial water change. As much as 50% even. Tap water has very low levels of oxygen in it. The waterfall and fountain should have been run continuously and faster if possible to get more air into the water. An air blower would have been ideal.

Now why the fish became stressed in the first place remains a mystery because I do not have the information but it was probably the result of lack of biofiltration (therefore ammonia was high) and lack of dissolved oxygen in the water which has a double effect .. fish gasp for air and biofilter bacteria also die which creates a worsening ammonia situation.

A kind of double whammy.

Putting the fish in the aquarium caused other problems like overloading the aquarium filter ... luckily the aquarium fish did not die .. and more stress (almost certainly different temperature)

This situation occurs to a lesser or greater effect in almost all ponds as they come out of winter and the water temperature increases and people start to feed their fish again.

I can say that the test kit was probably wrong based upon the observation that tap water was also off the chart ... this is almost impossible.

Vinegar was added to the pond which could be the correct way to lower pH if the pH was high in the first place ... but if was not high then a cycle of events was started that will create other problems. In any case how much vinegar was added and how was this amount calculated?

pH is a very complex variable in pond water and it also varies depending upon time of day and with other factors ... I can guarantee that measuring pH will cause more confusion and problems for the vast majority of pond keepers than not measuring it.

Let me be straight on this... test kits in the hands of garden pond keepers are dangerous. They often produce wrong results and action is taken based upon wrong result. Retailers love to sell test kits ... they are quite expensive and an opportunity arises to sell refills periodically.

Serious koi keepers will test water and monitor it daily over years but they will use the very best test kits available, check trends not once off results and use experience and fish behaviour to confirm probability of result being accurate.

Here's my summary of suggestions to bear in the front of your mind as spring approaches and water warms up ...

Do not test unless you really must .. and make sure test result is accurate and reliable and you know what it means and you have trend results to cmpare yoru individual test result with. pH is especially difficult to measure and understand.

Make sure you have a biofilter ... you must have heard me say this countless times. Yes it is important, very important if you keep fish. See link for the very lowest cost effective biofilter units I have come across ... and if you do have a pond filter already make sure it is cleaned out (use pond water) and that water flows through it 24 hours per day. A biofilter works very sluggishly at lower temperatures so spring problems can be expected or anticipated almost

Do use a fountain or preferably a waterfall 24 hrs per day to add oxygen to water

Do not feed fish when water temperature is still very low and when you do start feeding the fish do it very gradually .. ie a tiny little bit only.

Do install an UV if you can afford it .. see links for very low cost and effective biofilter and UV combination. You will never regret it. This is the best thing that ever happened to pond keeping

In my honest opinion the only products worthy of consideration for adding to a pond are biologically friendly mixtures which under correct conditions can help the biological activity in the pond without causing any other problems are those produced by Microbe Lift ... they must always be used as recommended otherwise they are a waste of money. Here's the link