Join Date: Aug 2010
Location: Central Virginia
Puzzling parameters in two tanks
I've been keeping track of params in my 13g almost daily. The KH has stayed constant at 2, GH was back and forth between 4-5. pH was at 7.4 for the first three days after a WC, then dropped to 7.2 for two days, then to 7.0 for two days. It's been five days since I've tested and today, WC day, it's 6.8. How is my pH dropping when my KH and GH are the same? There is a new piece of DW in the tank, but I thought my KH and GH would buffer that.
Second, in my 20g, the params are usually GH 4, KH 0-1 and pH 6.6. Since I moved my RCS to that tank, I added three coral rocks to it to raise the GH, KH and pH for them. So I tested today, checking if the rocks made any difference. The GH is now 8 (my tap is 6), KH is still 0-1 and pH is 6.8. I thought the coral rock would raise the KH but not the GH, and have a greater impact on the pH.
What's going on?