pH GH and KH explained

pH GH and KH explained in this article, as best I can. Water chemistry requirements for goldfish are often underestimated. At the same time it needs to be acknowledged that they require a stable PH and hence are susceptible to illness from a rapid pH change.

Goldfish benefit from a more exacting regime, and it can be said that there are health benefits, even if indirect, from careful monitoring and adjustment of these water quality parameters.

Now we will look in detail as to what these parameters are.

Persistence of Hydrogen (pH)

The PH of your water is a measure of the balance between the Hydrogen (H+) and Hydroxide (OH) ions in the water. I think most of us know that low pH is acidic and high pH is alkaline, or basically: a pH of 5 is slightly acidic water, a pH of 7 is neutral and a pH of 8 is alkaline water.
For the budding chemists the equation is pH =

PH GH and KH Explained

Water chemistry requirements for goldfish are often underestimated. At the same time it needs to be acknowledged that they require a stable PH and hence are susceptible to illness from a rapid pH change.

Goldfish benefit from a more exacting regime, and it can be said that there are health benefits, even if indirect, from careful monitoring and adjustment of these water quality parameters.

Now we will look in detail as to what these parameters are.

Persistence of Hydrogen (pH)

The PH of your water is a measure of the balance between the Hydrogen (H+) and Hydroxide (OH) ions in the water. I think most of us know that low pH is acidic and high pH is alkaline, or basically: a pH of 5 is slightly acidic water, a pH of 7 is neutral and a pH of 8 is alkaline water.
For the budding chemists the equation is pH = -log10[H3O+]

PH GH and KH Explained

Adjusting PH

1.Lowering PH

Filtering water over peat
Add bogwood to the tank
Inject carbon dioxide CO2
perform water changes with softened water or RO (Reverse Osmosis) water

2.Raising PH

Buffer using Bicarbonate of soda
Aerate the water, driving off the carbon dioxide (CO2)
Filter over coral, shells or limestone
Add rocks containing limestone to your tank.

Carbonate Hardness (K

PH GH and KH Explained

This is an area where a lot of people get confused. One of the reasons the term alkaline is avoided a bit and the term Basic is used for the PH scale is because this reading is measuring the alkalinity of the water. It is not the same as alkaline.
The alkalinity is a measurement of the waters buffering ability, or its ability to absorb and neutralise acid. The more alkalinity or the higher the Carbonate Hardness of the water the less likely you will incur PH swings in the water. It is therefore important to get this figure reasonably high to stabilise your water.

Adjusting KH (pretty much the same as adjusting your PH values).

Exactly how high you want your dKH (degrees of KH) will depend on what PH you choose to use. For goldfish keepers, our fish require very stable fairly high PH conditions, they do not like change and the conditions can be difficult to keep stable.

1. raising KH

use bicarbonate of soda
Aerate the water, driving off the carbon dioxide (CO2)
Filter over coral, shells or limestone
Add rocks containing limestone to the tank or use dolomite gravel

2. lowering KH.
Injecting carbon dioxide (CO2)
Use reverse osmosis (RO) water. You can mix tap water with reverse osmosis water to achieve the desired KH.

Do not use distilled water as it has no dissolved salts and hence no buffering ability.

General Hardness (GH)

This is essentially a measurement of Magnesium and Calcium ions in the water. Again it is measured in the German degrees of hardness scale or parts per million. This is what is generally meant by soft and hard water which are terms people should be familiar with. The table below shows comparisons between parts per million, the dH scale and the generalised concepts of soft and hard water. Goldfish prefer hard water with a GH of 180-280.

General Hardness Table

0 to 4 dH 0 to 70 ppm Very Soft
4 to 8 dH 70 to 140 ppm Soft
8 to 12 dH 140 to 210 ppm Medium Hard
12 to 18 dH 210 to 320 ppm Fairly Hard
18 to 30 dH 320 to 530 ppm Hard

Adjusting GH

1. To increase GH
Adding limestone to your aquarium (this will also increase KH which in turn will increase PH)
Adding calcium carbonate will raise GH and KH

2. To reduce GH
Adding peat moss to your filter
mixing tap water with reverse osmosis (RO) water

So how does this all relate to goldfish?
Here is the complicated part, should you worry about the sustaining the correct PH for a Goldfish?. Yes you should and for a number of reasons.

1. A stable pH environment is indicative of good water quality, a working filtration system and can put you at ease that your goldfish are in a good healthy environment. A healthy environment generally means healthy goldfish. If the PH suddenly swings it tells you something is wrong, before the goldfish gets sick.

2. Many disease agents that affect goldfish do best around neutral water. So if we keep the PH high, we eliminate fungal spores and have the water conditions set to minimise the risks of infections.

Therefore we recommend high PH conditions for goldfish. Certainly neutral and above anyway. Acidic conditions are particularly good for turtles and they also seem to do better in moderately hard water, rather than soft.

Testing the Water.
This is actually relatively simple. The commercially available test tube aquarium PH and Hardness test kits are certainly accurate enough. Follow the directions on whichever ones you buy and do the tests once per week to monitor your aquarium. Remember that when doing water changes you need to prepare the water so that it?s the same as what you removed. So if you add salt you need to add more. If you are maintaining a high pH and your local water is soft and acidic you must correct this first.

So how does this all relate to goldfish?
Here is the complicated part, should you worry about the sustaining the correct PH for a Goldfish?. Yes you should and for a number of reasons.

1. A stable pH environment is indicative of good water quality, a working filtration system and can put you at ease that your goldfish are in a good healthy environment. A healthy environment generally means healthy goldfish. If the PH suddenly swings it tells you something is wrong, before the goldfish gets sick.

2. Many disease agents that affect goldfish do best around neutral water. So if we keep the PH high, we eliminate fungal spores and have the water conditions set to minimize the risks of infections.

Therefore we recommend high PH conditions for goldfish. Certainly neutral and above anyway. Acidic conditions are particularly good for turtles and they also seem to do better in moderately hard water, rather than soft.

Testing the Water.
This is actually relatively simple. The commercially available test tube aquarium PH and Hardness test kits are certainly accurate enough. Follow the directions on whichever ones you buy and do the tests once per week to monitor your aquarium. Remember that when doing water changes you need to prepare the water so that it?s the same as what you removed. So if you add salt you need to add more. If you are maintaining a high pH and your local water is soft and acidic you must correct this first.

For the maintenance of high pH freshwater you should obtain a high range pH test kit as the standard kits usually only go up to 7.8.
Conclusion.
Put simply we all know we are keeping fish which have a very intimate relationship with water condition. It?s important to have good quality, clean, stable water for your goldfish. I do recommend high pH and hardness for goldfish, as I have said this is not because they cannot live in other conditions but because they do well in aquariums in this regime.

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