please post more details of your tank...any flora? imo a small 5 gallon tank can do quite well with just excel. It should work out cheaper that way too. Activated carbon does absorb nutirents but once it is exhausted it is quite useless in the filter. you would be better off by keeping sponge and ceramic rings in your filter. In a small 5 gallon tank a simple sponge filter with an air pump will do just fine. In fact that's what I am using in my 7.5G tank and the water cleared up in just a few days. What fish do you intend to keep in this tank?
thank you for your suggestions...here are the tank details.
Water:
all water is RO water as I use this exclusively on my reef tank. except I use water through the last stage DI (deionized water). i decided to use straight Reverse osmosis water without the DI part for the fresh water as DI is too soluble from what I understand for Fresh water fish. Correct?
substrate:
first layer pure laterite 2 OZ.
Miracle grow organic soil sifted\
third layer pure laterite 3 OZ.
capped layer Carib sea: flora max.
seperate carib sea samoa beach sand
Livestock:
5 small neon gobies
2 small fancy guppies
1 small ghost shrimp
1 small blue shrimp
1 small albino cory
1 small black and white striped cory.
2 gold snails
Fish are tiny babies, as fish get larger they will need to be given back to the store and I know this and prepared for it. right now though these are tiny fish. cory being the largest at .75" everything else is smaller).
plants:
by topfin- dwarf hairgrass - eleocharis parvula, Telanthera Cardinalis, 4" compacta - hygrophila Corymbosa Stricata, peacock fern - Selaginella willdenowii, also have this tall grass looking plant (sorry dont know the name but was told that its an easy plant by petsmart <oh boy hope thats correct). the above were suggested on line.