Paul's Aquariums & Ponds

Water Chemistry

Having problems with algae or sick fish?

The most common cause of aquatic death is due to extremes in water conditions e.g. pH or ammonia shock. This can be simple to treat. We offer a free range of water tests to all our customers and explain what the results mean and how to fix them. Come in and see us for more information.

Note: Water conditions are different all over Australia - what works for some people may not work for others. The information here is designed for a large range of water conditions in the Brisbane area.

Recommended water changes:

	A water change of more than 15% will quickly change the conditions of your tank. Many people will recommend a water change of 30% or more but be warned large changes will affect the nitrifying bacteria causing a build up of toxic chemicals like Ammonia and will quickly change your pH and water hardness.
	Many people will have a tank running for years without ever checking the pH , therefore don't think they need to, but as water in Brisbane gets worse it should make more sense to start testing your water. It’s just a matter of time until you hit dodgy tap water and this is the main reason for fish lost.
	Because tap water is forever changing in the amount of chemicals present (sometimes as often as every few hrs) its important to only do only small regular water changes (we recommend only 10% per week)
	The reason for this is even though you are adjusting the pH and adding chlorine neutralizer (water ager) there are many other chemicals present which if added to the tank in large amounts can make the fish sick or even cause them to die. Even up to a week after the water change has been done.
	Most chlorine neutralizers will help remove chlorine, chloramines and ammonia, but they will not alter the pH .
	pH is usually measured from a water sample and matched on a colour chart numbering from 1 – 14 with 7 being neutral.
	Numbers on the chart below 7 are considered acidic and numbers above 7 are alkaline. A reading of 7 is called "neutral" and is an even amount of acid and alkaline.
	If fish are kept in the wrong pH this will stress them and it is more likely they will get fungal and bacterial infections (yucky!)
	All tanks will benefit from small weekly water changes…even if you hit bad tap water 10% changes will not kill off your tank.
	It’s also important to mention that all water should be adjusted (pH and water ager) BEFORE the water is added into the tank.
	Nitrifying bacteria additives should be added directly into the tank not into the water change bucket as new water will kill off the bacteria.
	When changing 10% of the water weekly is a good idea to clean a small amount of the gravel bed using a gravel vacuum cleaner (don’t clean more than 20% of the gravel in one week as this can kill off a lot of nitrifying (good) bacteria)
	When changing /cleaning filters never use tap water to clean your filters. Take half a bucket of water out of the tank (depending on size of the filter) and clean the filter medium in this water.
	This will ensure the nitrifying bacteria in the filter won’t all be killed off by tap water or a change in water conditions. filters don’t have to be spotless to work… a filter with a good amount of nitrifying bacteria living in it will take longer to clog than a new sterile filter.

What about pH?

	pH is a measurement of how much acid/alkaline is in something. The scale is from 0 – 14 with 7 being neutral. Fish around the world mostly live between a pH of 5.5 and 9.5 Above or below this 99% of fish are pretty much toast! (dead)
	Most fish will need a different pH than your current tap water conditions. If fish are kept in the wrong pH it weakens there immune system and stuffs them up! Some fish will die quickly some fish will take years to slowly die.
	Fish living in the wrong pH can also become more aggressive towards other tank mates or can act shy, jumpy and nervous.
	Just because the water in your tank is clear it doesn’t mean your pH is “fine”. Some extremes in pH e.g. high amount of acid can make the tank look yellowish.
	Fish cannot be “adapted” to a different pH as it takes many generations to evolve to live in different water. A lot of people will tell you the fish they sell have been "adapted" to tap water, this is not the case as it takes a few hundred years to evolve to a different pH! - Sure the fish will be living, but as stated earlier they will have a weakened immune system.
	The pH of tap water is forever changing and is a lot different than it was a few years ago. It is now quite alkaline and not suitable for most tropical and coldwater fish, and is just below the right pH for African cichlids.
	If you don’t check your pH it could be very high (alkaline) or low (acid) as this has very slowly changed over time (fish waste/bacteria breaking up ammonia ect will affect the pH) your fish will look “fine” but any new fish going into that water will most likely get stressed, get a bacterial or fungal infection or the fish already in the tank will attack it because it is weak from the sudden change of water conditions.
	A lot of people think the fish they have had on its own for years cannot be kept with any other fish because of aggression , but its simply the water conditions that is making it more aggressive or the new fish introduced are suddenly placed into water far different than they have been living in therefore giving the original fish a reason to attack a weakened fish.
	Many people have a bad experience when first changing the pH e.g. the tank goes cloudy, this is mainly because the pH in the tank has been changed too fast, it's best to change the pH no more than one point e.g. from 7.5 to 7.6 in one day this means if you have a pH of 8 and you want a pH of 7 it should take around 10 days to get it down. you Can adjust your pH faster if there’s no fish or plants in your tank, but because Brisbane tap water is hard and alkaline the pH will tend to jump back up after a few days if you are lowering it.
	The difference between a pH of 7 and 7.1 is ten times more alkaline so the difference between 7 and 8 is HUGE!! When changing the pH its best to only use half a level tea spoon of pH up or down per 100 litres of water per day until the desired pH is achieved.
	pH is very important but there are a lot of other chemical changes that go on. If you are interested to know more feel free to come in and ask.