The Constituents Of Seawater

The seas and oceans cover the majority of the planet surface. Within those seas the wild reefs have grown and all of their needs are met, be that calcium or whatever. The life on the wild reef has had a very long time to adapt to the sea, which is considered to be stable.

Some of these life forms end up in the home marine aquarium. With the natural seas being so stable it follows that for success the conditions on the wild reef should be duplicated as near as possible, and conditions provided that successfully permit life to function and be healthy.

Seawater quality is the number one on the list of ‘must haves’ for success so it follows that the seawater used should be as close as possible in make-up to the natural kind. In much earlier days aquarists would obtain some constituents – not all of them by any means – from a chemist and mix up a brew. Livestock existed in this fairly well for a while but trouble usually appeared. Nowadays there are many high quality dry salt mixes available which the manufacturers state equals the natural type. Be that as it may, the appearance of these dry salt mixes has brought the successful maintenance of a marine system within the reach of every aspiring aquarist provided the interest in the hobby is maintained and the requisite maintenance is done.

Seawater is a mix of many things, some of them present in major amounts, others in trace amounts, and more with a very tiny presence. So for the benefit of anyone interested there follows a list of the make-up of seawater. There is clearly no requirement of any kind for an aquarist to know them but as said it may be of interest. It could also be of use for aquarists who wish to maintain natural levels of important parts such as calcium etc.

Major Elements. (All measurements in mg/l)

Chlorine	18880
Sodium	10770
Magnesium	1290
Sulphur	884
Calcium	412.1
Potassium	399
Bromine	67.3
Carbon	28
Nitrogen	15
Strontium	7.9
Boron	4.5
Silicon	2
Fluorine	1.3

Trace Elements. (All measurements in ug/l)

Lithium	180
Rubidium	120
Iodine	60
Phosphorus	60
Molybdenum	10
Zinc	4.9
Argon	4.3
Arsenic	3.7
Uranium	3.2
Vanadium	2.5
Aluminium	2
Barium	2
Iron	2
Nickel	1.7
Titanium	1
Copper	0.5
Cesium	0.4
Chromium	0.3
Antimony	0.24
Manganese	0.2
Krypton	0.2
Selenium	0.2
Neon	0.12
Cadmium	0.1
Wolfram	0.1
Cobalt	0.05
Germanium	0.05
Xenon	0.05
Silver	0.04
Gallium	0.03
Lead	0.03
Zirconium	0.03
Bismuth	0.02
Mercury	0.02
Niobium	0.01
Thallium	0.01
Thorium	0.01
Tin	0.01
Hafnium	0.007
Helium	0.0068
Beryllium	0.0056
Gold	0.004
Rhenium	0.004
Lanthanum	0.003
Neodymium	0.003
Tantalum	0.003
Yttrium	0.0013
Cerium	0.001
Dysprosium	0.0009
Erbium	0.0008
Ytterbium	0.0008
Gadolinium	0.0007
Praseodymium	0.0006
Scandium	0.0006
Holmium	0.0002
Lutetium	0.0002
Thorium	0.0002
Indium	0.0001
Terbium	0.0001
Samarium	0.00005
Europium	0.00001
Radium	0. 00000007
Protactinium	0. 00000005
Radon	0. 000000000006

Constituents with a tiny presence.

Technetium

Ruthenium

Rhodium

Palladium

Osmium

Iridium

Platinum

Astatine

Francium

Actinium

(Reference: ‘Baensch Marine Atlas’. Helmut Debelius & Hans A. Baensch)

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Tags: Aquarium Maintenance, aquarium salt, Aquarium Water, Care, Equipment, Water Quality

Which Aquarium Salt Should You Use

A long time ago, before I commenced keeping a marine aquarium, seawater had to be mixed by hand using ingredients that had been individually obtained from a chemist. The hobby books of the day, and they were very few, gave details of the mix. This mix was pretty basic, and contained very few trace elements and not many of the minor ones.

As time passed a few dry aquarium salt mixes appeared which had been produced commercially. They did contain most of or perhaps the entire major, minor and trace elements. It was discovered that nitrate and phosphate were unwanted as they had become known as nuisance algae nutrients, and the salt manufacturers made a great show of how their particular salt was free of them.

Now there are many commercial aquarium salt mixes available and they all claim to be ‘the best’. The mixes are now very consistent and considerable advances have been made in trying to emulate nature’s own, the seas and oceans. Some aquarists use natural seawater, and there are anecdotal reports that they have met with success, corals being really well extended and fish healthy. Most aquarists use a dry salt mix however, as it is convenient wherever the aquarist lives.

The production of dry salt mixes has moved on as the hobby has. No longer do marine aquarists struggle to maintain their livestock as technology and knowledge have made it easier. Aquariums that would dazzle those pioneer aquarists of long ago now exist - those where some of the most beautiful fish of the wild reefs are kept, and those where a living captive reef is maintained. Proper husbandry and knowledge plus technology make it possible.

The highest priority for any marine aquarium is the quality of the seawater. This is even ahead of lighting for a reef aquarium, the close second. Low quality seawater leads to problems and there isn’t any need for it. Modern sea salt mixes go a long way to providing this quality. The aquarist needs to be aware of the parameters that are required and maintain them, with supplementary additions if and as needed and routine seawater changes.

So all the aquarist needs to do is go to the local fish shop (LFS) or use the internet and buy what is needed. Basically, yes, that’s it - couldn’t be easier. There are a couple of things to bear in mind though.

The first is that which has already been mentioned. It would be unusual for a dry salt mix to be contaminated with phosphate and nitrate nowadays, but nevertheless the aquarist should be happy that it isn’t. Most manufacturers state the fact on the packaging.

Next the type of fresh water that is being used should be considered. Some aquarists use it straight from the tap, and others use RO (reverse osmosis) water. The latter is where the tap water has been passed through a very fine filter - ‘super-filtered’ it could be called. RO is the one that is recommended as it will have fewer impurities.

If the aquarist uses tap water then what perhaps is ‘ordinary’ salt could be used. This is where the mix contains the ‘standard’ amount of calcium, for example. Tap water contains amounts of calcium (which varies according to location) and there isn’t a need to have additional calcium in the dry mix. If RO water is in use then much of the content of the tap water will have been removed and a salt mix with extra calcium could be used to ensure that the level is brought up correctly. Actually, it shouldn’t be a disaster if either salt mix type is used with either fresh water type, tap or filtered tap, but the salt mixes are there so why not use them.

Then there are the mixes, as above, that claim to be suitable for reef use, as they have extra this and that which usually includes calcium. These find favour with many aquarists.

So choosing a dry aquarium salt mix nowadays is straightforward. There are those mixes that are very well known and have been in use for years, and there are more that could be just as good but are less well known. Perhaps selecting the type that a successful aquarist colleague uses is the best route, or one that is highly recommended on the internet and in hobby magazines.

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Tags: Aquarium Maintenance, aquarium salt, Care, Equipment, reverse-osmosis, Water Quality

Mixing Saltwater

Saltwater is going to be mixed many times from the very creation of the aquarium way into the future. It is my opinion that a lot of people make this into something which takes more time than it actually needs to be.

All you need to do is spend a bit more time when performing the first water change to make it a lot easier in the future.

Both John and myself recommend the use of reverse osmosis water be this purchased from the local fish shop or created in the aquarists own home therefore when purchasing the salt mix it is imperative that one be purchased which has been specifically manufactured to be used with reverse osmosis water.

The net gallonage of the aquarium should be known from when the aquarium was initially filled with water therefore it is relatively simple to work out how much water will need to be removed from the aquarium for a 10% water change to be performed. In this example we will pretend that the net gallonage of the aquarium is 100 gallons therefore a 10% water change would be 10 gallons. This figure should be noted down for future use.

It should be remembered that fresh newly created reverse osmosis water should be used and it should be heated up to the same temperature of the display aquarium prior to adding any salt.

Having purchased the sea salt it is fairly straight forward to ‘guess’ the amount required to meet the intended specific gravity of the aquarium by looking at the suggestions/recommendations of the manufacturer.

When measuring it is recommended that you actually measure slightly less than you believe you require. Once you have measured the salt do not add it to the water weigh it first and make a note of the reading.

Add the salt to the water and give it a really good stir using a device such as a clean wooden spoon to initially mix it in. Add either an air pump or a small powerhead and leave it alone for 8-12 hours. This will allow the salt to fully mix into the water.

After this time measure the specific gravity with a hydrometer or other measuring device such as a refractometer.

At this point you will have one of three scenarios:

1. The specific gravity reading is to low. Measure out a little more salt and make a note of the weight. Add this salt to the mixing device and allow more time for the salt to mix and then test the specific gravity again. If more salt is needed then proceed as before ensuring that any new salt measured it weighed and recorded. Once the specific gravity reading is correct then simply add all the salt weights together for future use and record this information.
2. The spcific gravity reading is to high. Add some more reverse osmosis water to the mix noting the amount added for future use. Give the water time to warm up and then test again. If the reading is still to high then add some more water and record how much was added. Once the reading is correct then add the amount of water together and record this information.
3. The specific gravity reading is correct.

Taking your time on your first water change will allow you to identify how much salt you need to add to the required amount of water. When new water changes are to be performed you can create the correct amount of reverse osmosis water and weigh out exactly the correct amount of salt required.

It needs to be noted that using this method although does save you considerable time when mixing saltwater does not mean that you should not test the specific gravity each time. It is recommended that you continue to test each and every time you create new salt water and always ensure that you keep your measuring device clean.

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Tags: Aquarium Maintenance, aquarium salt, Aquarium Water, Care, Water Quality, water-change