Quote:
Originally posted by Jeremy1973
... So, I would say if you keep the bioload light, you shouldn't have any problems. ... ...The protein skimmer just helps remove excess protiens and such from the water.
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Jeremy points out the biggest problem you will have, even with the skimmer. With a tank the size of yours (30 gal?) saltwater will support about 2 or 3 small fish, and that is about the limit. The problem has to do with the toxicity of nitrogen products in SW Vs FW. In a [b[closed[/b] system, the ability of SW to sustain and maintain higher vertebrates is much lower than that of FW. The exact number of inches doesn't come directly to mind, but I seem to remember a rule-of-thumb for 1 inch of fish for every 10 US gallons of saltwater. Increasing the level beyond this often outstrips the ability of the system to remove nitrogenous wastes from the water column. Much of the toxicity of these same nitrogen products is related to the higher pH of the water column (at an average of 8.2) as opposed to the lower (in general) pH of 7.0-7.1 of
most FW systems. (
Increasing the pH of a solution that contains ammonia or nitrite increases it's toxicity by the factor of it's rate of ionization. Unionized ammonia is much more capable of penetrating the lipid barrier of tissue, especially neurological tissue, and fish use a lot of this type of tissue to keep their bodies' salinity from becoming an issue in marine environments. Unionized ammonia can easily pass through the barriers to water molecules, as opposed to the charged molecules of the ammonia ion that exists at lower pH at the neutral levels of freshwater systems.) The problem then becomes not only problematic about the removal of nitrogenous (ammonia) wastes, but their very toxicity becomes a larger issue as well.
Skimming helps, it introduces a large amount of oxygen to the water column as well as removing the wastes before they are processed by eutrophic bacteria into ammonia (both fish and bacteria make ammonia out of proteins, fish as the end product of amino acid metabolism, some spp. of bacteria as the end product of their general metabolism (rotting, if you will...
) This is where your live rock helps tremendously, as it will further process (mineralize) organic nitrogenous products and ammonia into a form that will remove the toxic forms of nitrogen (as a gas) from your biotope altogether. This will complete the
nitrogen cycle in your tank (sorry, this is the VERY simplified form of this process). NitrATE then does not accumulate in your system, especially if your bioload is low, your input of nitrogen (proteins in the form of food) is low and you have a
Deep Sand Bed to further process nitrogen in your tank. You will be able to keep a fairly large number of compatible
corals and lower life forms in a small tank, but the number of higher life forms will be limited by the ability of the system to perform biological cycle completions for waste products.
Quote:
a note from Jeremy:
Also, forgive my ignorance...mollies? I know of fresh water mollies, but never heard of a salt water mollie...
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Interesting choice of fish, this is actually a fish from the brackish estuary areas of SE United States and Central America. They can often be found in ditches of runoff water from these areas and areas of delta deposition of silts where algae is abundant. They were formerly known as [Mollienesia spp.[/i], but are now known as
Poecilia mexicana and other related species. They are not truly FW nor SW, but can be acclimated to either environment, although this seems to shorten their life span considerably. If this is an option, I would suggest that you return these estuary fishes to the LFS and let the system mature for a bit without any fish, then make a decision (after much reading!) about which compatible fishes you may want to choose for your little slice of the ocean.
FW and SW mollies are the same, they have been acclimatized to the SW environment for this system. They can as easily go to FW, although the process of acclimatization should be slowly performed.
HTH
Welcome! heh heh
Esp. for a 20gal long... you probably should stick with no more then 3 fish. And I agree, you probably want to get some more LR. (a great thing to help with filtration)
