|Re: Substrate Question.|
Subject: Re: Substrate Question.
by Fishlady on 8/9/2012 14:27:44
It's a bit more complicated than that. Coral sand does buffer water but it does so slowly and to a limit and would never be used as the sole kH buffering system in a tank, especially where the level you need is considerably higher than the level in your supply. It's more usually used in combination with other carbonate buffers such as limestone rock and so on. Commercial buffers still need to be added to any water gong into the tank as all these soluble substrates and rocks take time to buffer the water. As soon as you remove any of the buffered water and replace it with fresh water that hasn't been buffered, the gH, kH and pH in the tank will drop, gradually rising again until the next water change.
If you are keeping fish who are in need of hard alkaline water and are also very sensitive to nitrates and organic waste (like Tangs), you'll need to be doing frequent partial water changes to keep conditions healthy. If your tap water is a long way below the required hardness and alkalinity needed for the fish, you will need a large amount of commercial buffer (or home made buffering powder) in every water change to match the kH, gH and pH to the levels needed in the tank. Buffers like coral sand and limestone can help prevent kH and pH from dropping between water changes and where the change needed is minimal, can buffer a lightly stocked tank using only a small amount of additives in fresh water.
If you choose to, you can skip the decorative buffers and do the whole job with commercial or home made buffers with the following caveats:
1) Tank must not be overstocked
2) Water changes must be done religiously at least once a week and more often if nitrates rise faster
3) Buffers must always be used in every water change and in quantities high enough to maintain a stable and suitable ph, kH and gH level over the time between water changes.