This webpage is designed to give readers more advanced information on water quality and how to ensure optimal water quality in any aquarium.  Aquaripure is dedicated to providing customers all of the tools and equipment needed to maintain optimal water quality at all times. 

pH

First, whether an aquarium is saltwater or freshwater, is is imperative that proper pH be maintained and that the tank be adequately buffered.  These are two slightly different concepts.  A buffered tank will resist pH fluctuation changes which can harm an aquarium.  To properly buffer a tank one should add sodium bicarbonate (baking soda) until it's pH just begins to rise.  After adding sodium bicarbonate, if the pH rises then the tank is adequately buffered.  Adding more will continue to increase pH until it is at it's proper level.  Calcium Carbonate or other compounds can also be used but baking soda is the cheapest and most readily available.  The buffering capacity is also known as kH but if adding baking soda increases pH then the buffering capacity is sufficient.  Always add baking soda very slowly and gradually.  One must avoid any sudden and drastic changed in pH.  Most pH tests, including those on test strips, can be hard to read or not particularly accurate which is why Aquaripure recommends an electronic pH meter, available on the product page. 

What is the ideal pH for your aquarium?  The best pH for a freshwater aquarium can range anywhere from 6.4 to 7.8 depending on the type of fish in your aquarium.  This is why it's so important to know your fish and make sure you obtain compatible fish for your tank.  If in doubt the 7.2 pH is a good target and most freshwater fish will adapt well to this pH.  For saltwater aquariums the recommended pH is 8.0-8.4 and 8.2 is an ideal target value.  pH should be monitored at least once every week or two and maintained.  To lower pH the best thing to do is do a water change with very soft water, either reverse osmosis or distilled water.  To lower it below 7.0 one can use peat moss but this is not really necessary for the majority of freshwater tanks.  A water softening pillow can also lower pH if necessary.  One must monitor pH even more carefully when a pH lower than 7.0 is maintained as it will have little buffering capacity.  

Nitrates

Monitoring pH is essential but it is a Nitrate test that will give the best indication of overall water quality once a tank is cycled.  Fortunately nitrate test strips are cheap and readily available that are about as accurate as any test kit.  It is widely accepted that nitrates over 40 ppm is generally harmful to fish and other aquarium animals.  In many tanks 40 ppm would be considered far too high.  High nitrates in a tank might be compared to humans living in an extremely polluted environment.  Some healthier people might not be as noticeably effected at first but more sensitive or weaker people will more readily succumb to illness.  There are many links and webpages on this website dedicated to nitrates and the effects of nitrates in a tank.   

It is essential that any beginning aquarist starting a new tank be very aware of the nitrogen cycle.  The is the process where a new tank becomes established with beneficial bacteria which breaks down organic molecules into nitrates.  There will first be a potentially deadly ammonia and then nitrite peak before the tank becomes established.  This process can last 8-12 weeks but will be greatly hastened using aquarium bacterial cultures such as found on the product page. 

Calcium, other elements and compounds, and Tap Water Filters

Just because nitrates are low and pH is ok does not necessarily mean that the water quality is perfect for your individual tank.  It is important to consider the water you use to top it off due to water lost to evaporation.  If this is not taken into consideration and only tap water is used then water quality potentially can degrade over time.  This fact is due to the fact that tap water in most areas is of fairly poor quality.  Most tap water is alkaline (has a high pH), has high levels of calcium, magnesium, and other metals and therefore is not suitable for water top offs in freshwater aquariums.  The levels of calcium, magnesium and other metals in water is directly related to both pH and hardness.  Tap water also contains chlorine, volatile organic compounds, and possibly other contaminants.  Fortunately there are a number of economical solutions to ensure the water in your aquarium remains of optimal quality and balanced.

For most saltwater aquarists tap water conditioned with a carbon block tap water filter is sufficient.  The water might still be slightly alkaline and have high levels of calcium and magnesium but this will help offset any natural drop in pH, calcium levels, and magnesium levels that normally occurs in most saltwater aquariums.  The carbon filter does remove chlorine, volatile organic compounds, and many other compounds not wanted in any aquarium.  Reverse Osmosis filters are generally not needed in saltwater aquariums as RO water will be very soft and low in pH and it just will mean more calcium and other trace elements will need to be added to the tank.

For freshwater aquariums most tap water will be too alkaline for water top offs or water changes and water that has a more neutral pH needs to be used.  Distilled water is one option but Reverse Osmosis water is just as good.  Aquaripure offers an economical Reverse Osmosis tap water filter which will last a year or more with normal use.  For those wanting an even cheaper option, rainwater collected in a large plastic container can possibly be used.  Rainwater is soft and has a neutral pH.  The only difficulty is making sure the container and water in it stays clean and uncontaminated.  To view all of Aquaripure's Tap Water Filters click here.

The best way to make sure what changes you need to make to your tap water or any other water source before using it in your aquarium is to test it for pH as well as nitrates, phosphates, and any other tests that you have for your aquarium.  If its not what you want your tank to be then it's not something you want to put in your tank.        

Using TDS and ORP meters to monitor water quality.

Although they are not absolutely essential, the TDS and ORP meters that Aquaripure offers can give you an idea of the overall water quality in both freshwater and saltwater aquariums.

The TDS in most municipal water supplies is quite high, often 300 ppm and even all the way up to 500 ppm or more.  This is completely unacceptable for any tank as it is both very hard and contains significant amounts of unwanted compounds.  It is also not even really recommended to drink.  Do you really want to drink water that has more dissolved solids and compounds in it than the average lake or river?  

TDS stands for Total Dissolved Solids.  A TDS reading will count not only contaminants but also things you might actually want in your aquarium water such as calcium, magnesium, and other trace elements and metals.  The TDS reading of most natural clean spring water will be between 100-200 ppm.  Most rivers and lakes would be a little higher, possibly up to 300 ppm.  This should also be at about the level of most water treated with a good carbon block filter although that might vary depending on the source.  Water filtered by a good quality carbon block filter and has some TDS but is free of chlorine and other harmful compounds is recommended for drinking water.       

Water filtered by a good quality carbon block filter that has some TDS but is free of chlorine and other harmful compounds is also suitable for saltwater aquariums.  This level will be ideal for top offs and water changes of saltwater aquariums as well as brackish water aquariums and other freshwater tanks where a relatively high pH is desired or acceptable.  Reverse Osmosis water is often cited as being required for saltwater tanks but RO water is not essential for top offs and water changes as long as the carbon filtered water is below 300 ppm and has little or no phosphates or nitrates. 

For freshwater aquariums where a more neutral or even acidic pH is desired then even a TDS reading of 100-200 ppm is too high for water top offs.  Distilled water and Reverse Osmosis (RO) water should be used.  Both distilled water and RO water should have nearly a zero or very low TDS.  Both conditioners to add small amounts of trace elements and a little baking soda to buffer the water is advised when using water this soft in an aquarium.

The TDS in a freshwater system should range 25-75 ppm or so for Discus and other fish that require very clean and soft water.   In most freshwater tanks 75-200 ppm would be considered an ideal range.  For a few freshwater fish such as some species of cichlids an average TDS of up to 300 ppm would be acceptable.  In nature fish might adapt to a wider range of variables but these would be considered ideal levels.

Aquaripure has measured the TDS in both seawater and various saltwater aquariums and the range was between 370-500 ppm.  A TDS in a saltwater aquarium above 500 ppm would likely indicate a water change and improvement in water quality is needed.  Some sources claim a TDS in the 1000's for saltwater is normal but this is untrue.   

ORP, or Oxidation Reduction Potential, can also be used to give a general indication of overall water quality.  ORP can be used in freshwater and saltwater aquariums.   If you want a detailed analysis of the use of ORP in aquariums then you can read this article but the basic information required to use it is here.  Basically if ORP is low then there are a lot of reducers in the water.  Reducers include a few other compounds but are mostly composed of organic molecules.  So if ORP is low then the water most likely has too much organic matter and compounds in it such as fish waste, uneaten fish food, etc. 

If ORP is high then that can mean there are a lot of oxidizers in the water.  The ORP is hot tubs should be at 600 mv or more.  This is because chlorine is an oxidizer and a hot tub should have a lot of chlorine in it to destroy ALL organic (including living) compounds.  You do NOT want your aquarium to be this high.  Ozone is sometimes added to fish tanks and ORP is monitored to make sure it doesn't go over 450.  That might mean too much ozone is present.  With an Aquaripure the ORP will typically rise and might even get as high as 500.  This is not dangerous in this case because this is not due to oxidizers being artificially pumped into the water but rather the reducers being removed.  However, you might want to add a little coral food if the ORP in a reef tank goes above 450 mv.   

In an aquarium an ORP value of 200-500 mv is acceptable with 300-450 mv being the recommended range.