Rolo

On another forum, I posted my findings when setting up a new tank with fluorite; the GH and KH dropped from where they were when coming from the tap. All that was in the tank was flourite, tap water, and circulated by an AC150 filter. People didn't seem convinced as they never experienced the same thing and pointed out some other areas they thought could cause the GH and KH drop.

So anyway, I did a very simple experiment that comes to a pretty much irrefutable conclusion. I set up two 20 gallon tanks. In one, just plain tap water, and in the other, tap water with brand new flourite. Both are being circulated by AC150 filters with brand new sponges. I checked the tap water parameters before and after filling, confirming they were the same. Right after fill I tested both of the tanks and confirmed they were the same.

2 days later.

Tank with tap water:
pH:8.2
GH:15
KH:21

Tank with tap water and Flourite:
pH:8.0
GH:10
KH:13

Well there you have it. In rare occasions Flourite will change your water parameters.

What sets my case apart from most is that my water is very hard. Carbonates (KH) are not very soluble, and with my high levels, I can only assume something in the flourite precipitated/bonded them out of solution. The Ca++ and Mg++ could have been collected at the CEC spots in fluorite, thus lowering GH.

Just wanted to know if anyone has had the same experience and theories of why the GH and KH decreased.

bharada

Well this is news to me, too. But if this does indeed happen I wonder how long the effect would last? I wouldn't mind getting my water hardness down a bit (my tap water sounds almost exactly like yours)...maybe I'd even have a chance with the L. 'cuba' that's not looking too happy at the moment . But if it's only a passing phase...

You should try extending your experiment to include changing the water in the Flourite tank and see if the new tap water continues to lose hardness or if it's just a matter of the Flourite reaching an equilibrium point in the initial fill.

Rolo

Yes, all I hope for is that this is a passing phase. I've already did a nearly 100% water change on the tank with fluorite to see if the parameters adjustements will stop. Will post results tomorrow.

I have no problem with flourite changing my parameters, for just a few times. What I'm not ready to have again is another substrate war, like this one I had some months ago. I had Shultz Profile that seemed to suck all the phophate out of the water column, which then releached it all back and I completely lost control of my water.