Water Changes - Why Are They Performed

Part of all aquarists maintenance routine should be performing a water change on the aquarium. Water changes are not just limited to saltwater aquarium - all home aquariums have a requirement for their water to be changed.

I was doing my water change today as part of my weekly maintenance regime and I thought to myself ‘how many people change the water without actually knowing why they are doing it…’

This article is aimed at owners of saltwater aquariums as there are slight differences between saltwater aquariums and other home aquariums - one of which is salt of course!

The recommended amount of water to be changed is 10% per week however this is not a figure which is set in stone as more may be changed if there are problems with the aquarium and less may be changed for various other reasons.

Due to the percentage water change this does mean that some people will be changing a small amount of water and others will be changing a lot more. Personally I have an aquarium where I am able to make up enough reverse osmosis water to perform the change. My aquarium is 100 gallons so 10 gallons is relatively easy to produce as my reverse osmosis unit is quite quick.

Other people decide to make up a large batch of reverse osmosis water and keep it for use until the container runs dry.

It’s whatever works best for you really.

If you look at the back of the box/container which the dry salt mix comes in you will see that it is made up of many things. This is one of the reasons why we change water.

The animals which we keep in the aquarium, especially corals, use some of what is in the water. Each of them has a different demand and slowly but surely the amount in the water is slowly reduced. When a water change is performed this element is added back to the water so effectively the element(s) being used are topped up which the livestock can then use.

One of these such elements is calcium. A lot of life in aquariums require calcium. When a water change is performed calcium is added back into the aquarium. For some aquarists this will be enough to maintain the calcium at the required level however for others they may need to use alternative methods to top up the calcium levels.

The replacement of required elements is a very important reason to change the water in the home aquarium however it is not the only reason.

Another reason we change water is that we are able to remove dissolved organic compounds from the aquarium before the filtration has had time to break them down. The protein skimmer attached to the aquarium can only process the water which flows through it and not all of the water in the aquarium will do so. It is recommended that when you perform a water change that you clean the rockwork as well. By blowing the detritus etc on the rock work in the water column this can be removed at the same time as the water. When a water change is performed some of the dissolved organic compounds are also removed and the water which replaces it is nice and clean.

If a sand bed is used for decorative purposes only i.e. it is not a deep sand bed or a plenum then the time when a water change is being performed is a perfect time for cleaning the sand. Stirring it is fine as all the detritus etc will flow up into the water column and can be siphoned out with the water.

When water is removed from the aquarium any nutrients in the aquarium are also removed. One of these is the dreaded nitrate. All aquarists aim for readings of zero when it comes to nitrate however water changes can be used to control nitrate. For example if you have 10ppm for nitrate in the aquarium and replace 10% of the water then your new reading should be 9ppm. Over time and with careful management this nitrate reading can be reduced further. Another nutrient which can be controlled/managed via water changes is phosphate.

Therefore effectively the main reasons we perform water changes is to add essential elements back into the water which have been used by corals, fish etc and also to remove nutrients, detritus etc from the water whereas if left they could be broken down by the filtration and become problematic.

I personally belive that water changes are one of the first things to be skipped when aquarists become lazy with the aquarium care and maintenance. At the end of the day we perform water changes so that we can attempt to achieve what all aquarists attempt to get - excellent water quality. If water changes were not performed then the fish, corals etc which live in this confined environment will be living in an environment which is not suitable for them.

Would you like to live in an environment which was polluted, full of nutrients and over time would make you poorly? I know I wouldn’t - so why make your livestock.

---

If you're new here, you may want to subscribe to our RSS feed. Thanks for visiting!

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

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.

---

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

Salinity In The Marine Aquarium

We all know that the fish and corals we keep are salt water creatures. That’s why we buy those expensive packets or buckets of dry salt mix.

Fish only or [tag-tec]reef aquaria[/tag-tec] are normally kept at a specific gravity (SG) of 1022 to 1026. It has been said that it is advantageous to keep a fish only system at 1022, as it is claimed that certain pathogens do not do well at a lower SG. Fish can be treated for some infections by lowering the SG even more. Reef aquaria are normally kept at 1024 to 1026, this seems to be the usual. [Read more]

Tags: aquarium, Aquarium Water, aquarium-saltwater, mix-salt-water, mix-saltwater, water-change

Performing a water change

Looking around on You Tube I found a video about performing a water change.

It’s quite a well done video, very well put together. There are a few things that I think should have been included in it for example the water is just poured into a bucket and is not heated up to temperature first. Of course you can perform a water change with cold water if you have a [tag-tec]large aquarium[/tag-tec] but if you have a [tag-tec]micro fish tank [/tag-tec]or [tag-tec]micro reef tank[/tag-tec] then I would not recommend it.

[Read more]

Tags: AQUARIUMS, mix-saltwater, saltwater, water-change