Salt water parameters for your new marine tank

Taking the mayhem out of marine fish keeping

The Marine Tank Environment

salt water parameters


It might seem a bit crazy, if you have just taken everything out of your water as suggested in the previous section and now you're going to put a load of things back in. The main difference is you will be putting things back in in known quantities. The things we're referring to are elements that are crucial for the survival of your tank inhabitants.


These elements are things like: Calcium, magnesium, strontium, boron, bromide and manganese.


Just about any marine brand salt on the market wil do the job but you will find different salts are suited for different tanks. Some salts are just good old marine salts and will maintain your FOWLR or soft coral tank with no problems at all. Some salts, however, have higher levels of this and that designed for accommodating the higher demands for elements made by some sps.


I fell into such a trap a while ago whilst restocking with some sps corals. I didn't have many and was using a brand of salt with high levels of magnesium. as I didn't have enough corals to use all the magnesium it wasn't long before that particular element was off the scale in my tank because nothing was using it.




The ideal parameters you're looking for are those with similar levels to natural seawater. As we're talking about simple marine tanks set up on a minimal budget I'll just touch on the parameters you will need to keep an eye on the most.


Of the 70 elements found in seawater you will only be worried about a few of them and many of us rely on the fact the other 65 or so are just included in the marine salt you buy. This won't be a problem for the average hobbyist keeping a simple FOWLR or soft coral tank. Indeed I have kept successful LPS tanks just relying on the elements provided in the salt added through water changes without worrying about all the trace bits and pieces.


The elements mentioned are those use by your marine tank inhabitants for survival, your inhabitants, however, whilst busy thriving in your tank will be producing waste products which will lead to ammonia, nitrite and nitrate. You also need to consider this when maintaining your water and ensure their levels are kept in check. Whilst the saltwater elements are provided by introducing salt to your tank, the wastte products will be managed by your filtration system (see the 'stocking your tank page for more details)




You will need to keep an eye on your salt levels, also known as your salinity or Specific Gravity (SG) level, this wants to be stable at 1.026 SG (specific gravity) or 35 ppt (parts per thousand) salinty. The most trusted way to measure your salt levels is using a refractometer or if you're a little more old fashioned like me a hydrometer. You salt level should always be tested at the temperature your tank should be stable at which is approximately 25 degrees centigrade.




Your pH is a measure of the acidity or alkalinity of your tank. This is influenced by the interactions between your marine organisms and by there inevitable production of waste materials. Your idea pH levels should be stable at approximately 8.1 to 8.3. This is towards the more alkaline side of the scale (where pure water is 7.0 and acidic is below this value) pH is easily measured using one of the readily available test kits.




Ammonia comes from the waste produced by your tank inhabitants. It's part of whats referred to as the nitrogen cycle (see the 'cycling your tank page') for the purposes of this page it's enough to say you should only ever have ammonia readings in the very early stages of setting up your tank, before you have introduced any livestock. Ammonia is toxic to your marine inhabitants at any level, any ammonia readings after you have intorduced livestock will be of immediate concern. There are many test kits available for monitoring your ammonia levels and it must always read 0 after the initial cycling process.




This is also a product of the cycling process and your marine tank should never have nitrite readings after it's cycled. If you come from a freshwater fish keeping background you will already know that any traces of nitrite will soon be fatal to your fish. Although marine fish can tolerate a tiny bit of nitrite if you are reading any at all your tank needs looking at immediately. As with ammonia, nitrite will be produced from too many waste products in your tank that the filtering bacteria can't deal with and you can get 'spikes' if, for example a fish dies and starts to decompose. Again there are many suitable test kits on the market for nitrite and you must always strive for a reading of 0/




This is formed at the end of the cycling process and is far less toxic to your marine tank inhabitants than the previous two. For a perfect set of parameters you are looking to run a tank with a nitrate level of less than five parts per million. This can be quite hard to achieve, especially if your tank is heavily stocked. Higher stocking level = higher amount of waste = higher levels of Ammonia, nitrite and nitrate. I have kept successful soft coral tanks on nitrates higher than 30 (this is not recommended) and most FOWLR tanks will have high nitrate levels. If you want to go down the road of SPS, however you will need to put measures in place to ensure your nitrate levels are very low otherwise you will end up with a forest of dull, lifeless looking twigs rather than the superb, colourful medlley of sps deliciousness you were probably aspiring to.




This will be your constant companion throught your marine fish keeping hobby and most marine fish keepers running budget tanks without reactors and all that gadgetry, spend more time worrying about phosphase and trying to reduce it than on anything else. Even the simplest and cheapest tank will almost always need some sort of help removing phosphates and this is usually done using a removal media. If, like me, you are running a super simple tank with no sump (see the equipment page) then you will put the media in a chamber in your protien skimmer. If you have a sumped system the media will go in there, either in a reactor (additioinal cost) or enclosed in filter floss in one of the chambers. Your ideal phosphate levels should be at or below 0.03. As your levels rise higher than this you will start to see algae developing which can become a real eyesore and once established it is very hard to remove.



This is more important to consider if you are thinking about keeping LPS or particularly SPS corals. The chemical equations for the use of alkalinity is beyond the scope of this website for now but we can think of alkalinity as a measure of the ability for hard corals to build new skeletons. You should be aiming for an alkalinity of between 7-11 dKH and again you can find many test kits available for measuring this element.




Again this is more important to consider if you are keeping hard corals although you should always try to keep your marine tank parameters at optimum levels regardless of the stock you keep. Hard corals take calcium out of their suroundings to build their skeletons. As a result if you have a tank with lots of hard corals in it the calcium levels will be depleted far quicker than if you just had a FOWLR or soft coral tank. This has a knock on effect for costs, if you have a high load on calcium you will have to consider adding supplements almost on a daily basis which will add financial pressure to your tank. You should aim to maintain a calcium level of around 420ppm (parts per million). There is some leeway either side of this value but again I stress the key is stablity. If your tank is stable at 450ppm or 410ppm that is far batter than it jumping around all over the place whilst you forever try to achieve the perfect level.


All of the above are an indication of what you should be aware of and prepared to check on a regular basis, I will go into more detail on all of these and more as this website develops and grows




Helpful tips


So what parameters do you need for your marine tank


Don't stress out too much over yur parameters, if you keep up with a good, weekly maintenance regime that should be all you need to keep a simple marine tank in tip top condition


If you're going to worry about any parameters then worr bout phosphate. Throughout the life of your marine tank it will be a constant pain in the back side

The parameters of your Marine Tank - in a nutshell

Some parameters that you test for are elements that are found in natural seawater and are necessary for the survival of your marine tank inhabitants

Some parameters you test for are a product of waste from your marine tank inhabitants and need to be kept at minimum levels

The stock list of your tank will dictate which paramters become more important than others.

Always keep ammonia and nitrite at 0, these should only be present in th very early stages of setting your marine tank up

You will record very different parameters during the early stages of your marine tank, see the cycling your tank page for more details