Planted Tank Enthusiast
Join Date: Nov 2004
Location: Los Angeles, CA
Why would KH go down?
ok, I'm a little confused --
When I set my tank up last week, I had a KH of about 5-6, with a pH of about 7.2-7.4. Today, after a week of pressurized CO2 injection controlled by a Milwaukee controller I'm getting a reading of 6.8 pH on the controller LCD and likewise a 6.8 pH reading from my Aquarium Pharmaceuticals test kit. So far, so good. (My tests kits use drops)
Then I went to test my KH with my Aquarium Pharmaceuticals KH kit (same one from earlier in week), and now my KH is reading is down to a 3.0 - low 4. Tested twice, same results. I also tested a sample of tap water: it was still a KH of 5 - 6 (just like when I first filled the tank).
What gives? I though KH was suppose to remain constant. No rocks, wood, or modifiers in my tank/filter. Just 100% Flourite. Some Water Sprite and Val and a few Angels.
At 6.8ph and 3KH I'm still providing a "good" level of CO2 (about 14ppm). BUT I was really hoping for the 20-25ppm of CO2 a KH of 5 would have provided me at 6.8ph. Any thoughts? Should I go lower to a pH of 6.6 or 6.7 (assuming KH stays at 3)? Is that dangerous? Not sure how folks usually go.
thanks as always