What are the advantages of water changes?
• It will freshen up the environment and disperse any build-up of organic waste.
• A water change helps to replace trace elements.
• Water changes help the growth of corals and fish.

What are the disadvantages of water changes?
• Don’t use water changes to disperse waste because this will cause a chemical fluctuation. To avoid this, increase filtration and the frequency of water changes, even decrease feeding. When the water quality deteriorates and waste levels bank up, doing a water change will dramatically clean and alter the environment. This is a fluctuation you would be best without.
• Large water changes tend to introduce a large amount of silicates and phosphate that may spark new outbreaks in algae if you are not using R.O. water.
• Large water changes can expose the corals at the top of the tank, this may cause some species to get an air lock or even pop as a result of its weight laying on sharp objects like its own skeleton. So be selective which types you place above the water change lines.

How often should I do a water change?
• In a new tank like to suggest you do regular water changes (10% every 1 or 2 weeks).
• As the aquarium gets older and more stable less water changes can be tolerated (e.g. 15% per month) as long as the parameters are regularly checked.
• Try to create an environment that shows a good logbook read out before you even do a water change.
• The water change should be considered to freshen up the environment not to clean up the environment- this will create a more stable result.
• Powerful biological filters (nitrification) increase the need for water changes.
• A tank may need 20-25% water changes per fortnight if it is well stocked with fish. The more fish, the more water changes need to be done.

What is the least amount of water changes I can get away with?
• If you have a mature stable aquarium with protein skimming and live rock you may choose to decrease your water changes.
• This is safe as long as you maintain your log book and keep a good eye on the tank.
• Some very established tanks can get away with changing as little as 10% of the volume each year as long as all is well.
• A tank with low water changes must only ever increase stock very slowly.

Should I let the water stand before I add it to the tank?
• Yes, it is best to aerate the water and let it stand (the longer the better).
• This will stabilize the pH and salinity plus lower silicates, phosphates and organic waste.
• If you are experimenting with the length of time that the water is being left unaerated, it is advisable to check parameters before you add it to the tank. This is because the initial micro-organisms may die off, creating a pollutant and a new cycle. The water will be good again in a few weeks.

What is the black stuff at the bottom of the drum of saltwater that has been left to stand for a period of time?
• This is the result of the lack of oxygen in the drum that has created anaerobic conditions resulting in hydrogen sulfide/sulfate (the black stuff).
• If you check the parameters of the water in the drum you should be able to use the water, as long as you try to avoid the black stuff getting into the tank. You may choose to siphon off the black stuff then use the water or use the water, leave the black stuff on the bottom and throw it out later.

Why is it that after water changes white snow seems to rain in the tank?
This can be the calcium precipitating as a result of very high calcium levels in the water that you are adding (this can also happen with water harding agents).

Can I use tap water in my tank?
• Tap and well water should be tested for nitrate and phosphate.
• Don’t use hot water from the tap in your tank because it will have higher levels of copper in it.
• If you run the water from the tap for a few minutes before using it you may minimize the metal in the water because there is less chance that is has been allowed to sit in copper pipes.

How do you purify freshwater?
• High quality distilled, de-ionized and spring water is safe for use; cheap brands may be impure e.g. contain copper.
• De-ionized then R.O. Water is the best and most pure way to top up the aquarium. R.O. is the most popular.
• If R.O water is not available to you, use aged tap water.
• Normal drinking water purification systems have a cartridge that must be replaced regularly so they work out to be very expensive for aquarium use.
• Diatom filters are good for water purification.

How should I top up the water that has evaporated out?
• Remember salt does not evaporate so the tank must be topped up with fresh water.
• It is possible to lose as much as 1% of your water capacity per day due to evaporation.
• It is advisable to place a mark on your sump to enable you to monitor the rate of evaporation, and if you don’t have a sump place a mark on your tank.
• It is best to add new water to the tank to counterbalance the evaporation as soon as you notice it has dropped from the mark.
• It is advisable to compare the hardness of the new fresh water because it is generally lower then the tank so it may need buffing.
• Watch the temperature of the new water is not much different to the tank. When you are adding fresh water to a tank it should be done gradually.
• It helps to place the amount of water that you wish to add into a bag and float it in the tank for about half an hour this will ensure the new water is the same temperature as the tank and will create less impact.
• Check the levels of waste e.g. nitrate and phosphate are low in the new water.
• If the water level in the tank is low when you do a water change ensure that the new water has a lower salinity to compensate for the possibly higher salinity in the tank due to evaporation
• In a reef tank it is wise to use kalkwasser as the top up water.

QUESTIONS ON OBTAINING SALT WATER

Should you test new water before adding it to the tank?
• This is an obviously wise practice, especially if you are changing the method of obtaining new water.
• All types of water fluctuate in quality.
• It is even good to add the results to your logbook.
• If you are using the same method each time and obtaining the same results each time you may decide not to test it.

What is better natural seawater or artificial salt mixes?
• I believe one way is no better than the other is because I have seen successful tanks run both ways as long as you ensure that the circumstances and condition of the water you add to the tank are favourable.
• Both tap water and seawater fluctuate in quality from time to time.

How do I make up artificial salt water?
• It is best to get a drum or spare tank that contains an aerator and a heater. The aerator is used to stir the water and dissolve the salt and the heater is necessary to give you an accurate salt reading (most hydrometers are only effective at a temperature of 25’C).
• Fill the drum with fresh water then add water ager.
• Test the pH of the fresh water; it should be abound 7.0 to 7.2. If it is too high you may have to lower it (use a lowering solution that doesn’t contain phosphate) before you add the salt or the buffers in. The salt mix may buff the new salt water too high.
• Add the salt (most salt mixes will tell you on the bag approximately how much to add for the desired amount of water).
• Get the temperature of the water to 25’C and ensure the salt level is desirable e.g. about 1.022.
• It can be wise to check the total chemistry of the water before you add it to the tank, so you are able to make any adjustments before it is used e.g. add a phosphate sponge to the new water before it is added to the tank.
• If the bag of salt is being stored, keep it dry and sealed at all times.
• How fast a salt dissolves has no relevance on it`s quality.
• Salt mixes shouldn’t be used straight away once they have dissolved. It may visually dissolve quickly though it takes 1 to 2 days for it to dissolve properly and for the pH to stabilize. It should be aerated.
• It is best to select a known brand of salt and stick to it so you become familiar with the quantity to use and the results. If you change brands, carefully document any change that may occur as a result of the switch.
• You can alternate brands in an attempt to get any advantages that either may offer e.g. wider range of trace elements
• To find how much waste e.g. NO3, PO4 the salt mix contains add the salt to distilled water and test it for them. They should read low.

What are the advantages of using natural seawater?
• It is free if it is in your local area.
• It can be used straight away.
• There are people that will deliver it to you so you can store it in an aerated drum until you require it.
• It contains natural microorganisms e.g. plankton that can be a food source for fish and inverts.
• You don’t have to add trace elements or liquid food when you do a water change with natural seawater because the organisms like plankton can be eaten.

What are the disadvantages of using natural seawater?
• You may introduce pollution.
• It can sometimes prove to be problematic to get and bring home.
• It tends to be higher in salinity than most aquariums, so it needs to be altered.
• It is rare though possible that disease, bad bacteria or parasites may be introduced though microorganisms e.g. plankton.
• If the water is not used quickly the microorganisms may die and pollute the water.

What are the advantages of artificial salt mixes?
• You know what you are getting, especially if you use R.O. water.
• It is relatively easy to transport.

What are the disadvantages of artificial salt mixes?
• It can be expensive.
• It takes time to make up.
• Some tap water is unacceptable for use, so you may need an R.O. unit.
• Some tap water can have a high pH this means you may have to lower the pH of the fresh water before you add the salt mix because the salt mix should contain enough buffers to convert a fresh water pH of 7.0 to a salt water pH of 8.0. Be careful cause some pH lowering chemicals can increase the phosphate level of the new water.

What can you do if your tap water proves to be unacceptable for use?
• You may need to buy R.O water from your local aquarium store or invest in a Reverse Osmosis unit to purify the fresh water.
• If you find out what it is that makes the water unacceptable you maybe able to fix it e.g. get a sponge to absorb the high silicate or phosphate levels.

Should I use my drinking water purifying system to filter the freshwater that I add artificial salt to for water changes?
• It is not recommended that you practice this because it softens the water and cause other problems.
• They work out to be very expensive.
• Try to use R.O units.

What do you look for when collecting natural seawater?
• The presence of oil on the surface of the water is a good indication to give it a miss today.
• Ensure that the water looks clear and the surrounding environment is visually healthy.
• It is not advisable to collect the water after heavy rain because of lower salinity and possible run off from the shore e.g. fertilizer or pesticides can pose a problem.
• The water can be better if collected from an incoming tide.
• Less risk tends to be faced if the water is collected off shore. If you are getting the water by boat turn the motor off and allow the boat to drift before collecting the water. This is to prevent picking up slicks created by the boat motor.

How long can you store collected seawater?
• It should be used straight away, if it isn’t, it should be aerated until you use it.
• Aerated water should be safe to use any time.
• If the stored water is not aerated the microorganisms will die and pollute the water. This will spark a new biological cycle, which will enable you to safely use the water after about 2 weeks once the new cycle is complete.
• This is why water left to stand should be filtered or at least aerated. If you feel that there are dead microorganisms in the water that you need to use there are micron filter bags or media available that you may pour the water though, which should mechanically remove such problems.

What should you use to contain your water?
• Glass tanks and Plastic drums or buckets are good selections.
• Don’t use metallic buckets for water changes or storage.
• A new plastic garbage bin is popular for making up and storing saltwater.

What is the brown substance at the bottom of the fresh unaerated water?
• An accumulation of a brown settlement may occur. This is dead microorganisms and it’s quite natural.
• Try to avoid this getting in to your aquarium, by siphoning it out first or not using the last bit of the water.

Why does the seawater smell after about a day if it is left unaerated?
• This is quite common and natural with the presence of the dead microorganisms.
• The smell should be gone after a week.
• You may wish to add activated carbon.

By Paul Talbot