What was the impact, if any, of Flourite/laterite on the hardness (GH) of your tanks?
There shouldn't be any... *but* a batch I put in my 10 gallon before Christmas... well, you can read the thread yourself! (http://ovas.ca/index.php?topic=12458.0)
Whatever was wrong with it seems to be gone now as my gH and kH are extremely low.
No question, it is the Flourite!!
I have Flourite in my tank. My tap water is GH=40, pH=8.4. My tank tests for the first 3 weeks have gone like this (only plants in tank until the 7th):
Date pH GH
2 7 280
7 7 180
9 7.1
10 7 140
12 7
15 7.2 180
16 6.9 140
18 6.8 140
20 6.8 120
Since it took a full week (and much filter floss) to get the water clear I think much of the "GH" was removed by then. I'm confident that my GH will continue to drop as the water stabilizes.