I ordered a GH and KH test kit because I am interested in breeding South American fish, which requires low pH for optimal breeding conditions. It finally arrived yesterday but I didn't get a chance to test my water until this morning. I tested every tank of mine including a bucket that's soaking Malaysian driftwood for two days and three nights.
The results have been interesting.
1.) Water straight from the tap - 7.6 pH, 3-4 drops of KH, and 4 drops of GH, which would indicate 71.6 GH/KH
2.) 40 Gallon Community Tank with Three Driftwood - 6.6/6.4 pH (color hard to tell), 1-2 drops of KH, and 2 GH, indicating 35.8 GH/KH
3.) Bucket Soaking Malaysian Driftwood 5 Gallon - 6.4 pH, 2 drops of KH, 2 GH, indicating 35.8 GH/KH
4.) Red Cherry Shrimp Breeder 20 Gallon - 7.6 pH, 4-5 drops of KH, and 9 GH, indicating 161.1 GH/KH
5.) Fire Belly Newts 20 Gallon - 7.6 pH, 4-5 drops of KH, and 6 GH, indicating 107.4 GH/KH
6.) Blue Pearl Shrimp 10 Gallon (set up 2-3 weeks ago) - 7.6 pH, 3 drops of KH, and 4 GH, indicating 71.6 GH/KH
7.) Mystery Snail and Espei Rasboras 10 Galllon with Mopani Driftwood - 6.4 pH, 1-2 drops of KH, and 7 GH, indicating 125.3 GH/KH
8.) Blue Crayfish, Cherry Barbs and Opaline Gourami 20 Long Gallon - 6.4 pH, 1-2 drops of KH, and 4-5 GH, indicating 71.6-89.5 GH/KH
I've come to the conclusion that my water has a very low buffer, explaining the differences between those tanks that have driftwood, and those that do not. Interestingly, it seems that the Blue Crayfish's pH has been lowered by the slate rocks that are in it since the tank has no driftwood. Otherwise, those tanks without driftwood or rocks' pH have remained the same as the water straight from the tap.
I can explain the high GH of the Red Cherry Shrimp's Breeder tank - I don't do water changes often with that tank since the Najas Grass effectively takes care of the majority of nitrates. Also, some water has evaporated, leaving the water level a little bit lower than the rest of the tanks, so the minerals are a bit more concentrated.
However, the Fire Belly Newts' tank water has recently been changed, with only maybe 30-40% of the old tank water still left. The general hardness of this tank shouldn't be as high, yet it is. Perhaps the plastic mesh has somehow raised the GH? The FBN and RCS tanks are the only tanks that I use plastic mesh in. The Newt's tank has much more mesh than the RCS's so it might not be that.
My goal is to lower my pH closer to 6.0. I believe that it's possible to dilute my water to that pH with driftwood in the tank. How do I further lower the pH? I know distilled water has a base of 7.0 pH so that's not the route to go. The only other answer is RO water or bottled spring water.
Here is a site listing the pH of bottled spring water - Bottled Water pH List
What are your thoughts?