Hate to clutter but........
And Byron what fun would life be if we agreed 100%?
Licorice are difficult fish to keep, usually not for the beginning hobbyist.
http
/www.reef2rainforest.com/2012/08/28/licorice-gouramis/
Byron, you have planted tanks and likely never have nitrate issues. The cycle itself is a natural pH lowering process. This is why old tank syndrome features greatly lowered pH. I think in your case something else was involved. Some crushed coral may contain something else?
To raise both GH and KH simultaneously, add calcium carbonate (CaCO3). 1/2 teaspoon per 100 liters of water will increase both the KH and GH by about 1-2 dH. Alternatively, add some sea shells, coral, limestone, marble chips, etc. to your filter.
To raise the KH without raising the GH, add sodium bicarbonate (NaHCO3), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.
from
http/fins.actwin.com/mirror/begin-chem.html#altering
Calcium carbonate is not hugely water soluble. So it will have less of an affect than adding calcium carbonate.
But lets look at the other effects. Let's assume adding the crushed coral doubles his GH and KH, it is still very soft water. Let's assume that it triples them, and it is still very soft water. Mine is TDS 83 ppm and it is soft water. that is down from 106+ 14 years ago, and then it was still considered soft
3dg GH and 3 dg KH still are considered soft even at 107 ppm. Unless one is keeping wild fish imported from acid environs, fish like tetras etc. should be just fine in that.
I made it very clear that the baking soda was only to be used during cycling, that the sodium would have to be removed before any fish went in
A buffer is typically an additive that uses two things in combination to hold water at a designated pH level. Adding KH will not target a level it will simply work to prevent dropping and then ic can raise the pH of acid water some.
Acidic buffer solutions
An acidic buffer solution is simply one which has a pH less than 7. Acidic buffer solutions are commonly made from a weak acid and one of its salts - often a sodium salt.
Alkaline buffer solutions
An alkaline buffer solution has a pH greater than 7. Alkaline buffer solutions are commonly made from a weak base and one of its salts.
from
http/www.chemguide.co.uk/physical/acidbaseeqia/buffers.html
Go to the Seachem site here and you will see they target pH by mixing their acid and alkaline buffers in different proportions.
http/www.seachem.com/Products/product_pages/AcidBuffer.html
http/www.seachem.com/Products/product_pages/AlkalineBuffer.html
Basically, the bacteria use the carbonates from KH as their carbon source. The baking soda will get this into the water instantly whereas the coral takes some time to work. So the former works better during cycling while the coral etc. works better afterwards. And crushed coral is not a buffer, it is a way to add carbonates to a tank with the calcium coming along as well. Here is how the same source above states it:
Buffering Capacity (KH, Alkalinity)
Buffering capacity refers to water's ability to keep the pH stable as acids or bases are added. pH and buffering capacity are intertwined with one another; although one might think that adding equal volumes of an acid and neutral water would result in a pH halfway in between, this rarely happens in practice. If the water has sufficient buffering capacity, the buffering capacity can absorb and neutralize the added acid without significantly changing the pH. Conceptually, a buffer acts somewhat like a large sponge. As more acid is added, the ``sponge'' absorbs the acid without changing the pH much. The ``sponge's'' capacity is limited however; once the buffering capacity is used up, the pH changes more rapidly as acids are added.
Buffering has both positive and negative consequences. On the plus side, the nitrogen cycle produces nitric acid (nitrate). Without buffering, your tank's pH would drop over time (a bad thing). With sufficient buffering, the pH stays stable (a good thing). On the negative side, hard tap water often almost always has a large buffering capacity. If the pH of the water is too high for your fish, the buffering capacity makes it difficult to lower the pH to a more appropriate value. Naive attempts to change the pH of water usually fail because buffering effects are ignored.
In freshwater aquariums, most of water's buffering capacity is due to carbonates and bicarbonates. Thus, the terms ``carbonate hardness'' (KH), ``alkalinity'' and ``buffering capacity'' are used interchangeably. Although technically not the same things, they are equivalent in practice in the context of fishkeeping.
And lets not forget what KH stands for-
Carbonate Hardness.
Look at what is in Equilibrium:
Soluble Potassium (K20) 23.0%
Calcium (Ca) 8.06%
Magnesium (Mg) 2.41%
Soluble Iron (Fe) .011%
Soluble Manganese (Mn) 0.06%
from
http/www.seachem.com/Products/product_pages/Equilibrium.html
Calcium yes, carbonates nope. Magnesium yes, carbonates no. Potassium also raises TDS. The Fe and Mn are very negligible. What I suggested is intended to add carbonates mostly and some calcium. And with every weekly water change it is reduced and then will take some time to build back up.
I went through all of this in 2011 on planet catfish in a thread I started.
http/www.planetcatfish.com/forum/viewtopic.php?f=5&t=33073
