Why Is My Ph So High?

[MeanHoney]

I have my tank for about 6 months and the PH is at 8.4. I've done huge water changes (over 50%) and it remains the same. I just set up a new tank and the PH there is 7.6. I'm using tap water in both. So the only difference would be the decorations. The tank with the high PH has gravel on the bottom, some fake plants, three ceramic decorations and what looks like a lava rock with a hole in the middle. The other tank has sand, a pot and some fake plants. Any ideas why the PH is so high in the one tank??

 

[littlelegs]

Have you tested the water that comes out of your tap?
Do you treat your tap water before you put it in your tank?

 

[MeanHoney]

Have you tested the water that comes out of your tap?
Do you treat your tap water before you put it in your tank?

The water in my new tank is right out of the tap. It's been sitting for about two days. When I do a water change I only put in some dechlorinator.

 

[pica_nuttalli]

it's probably the holey-rock. many of those will buffer your water, resulting in a higher pH

 

[MeanHoney]

Thanks Pica. I'll try taking that rock out and see if it helps.

 

[Anita]

Try adding some bogwood if you want to lower your pH a little.

Anita

 

[eschaton]

Yeah, that rock (if it's the same rock I got at Petco) is actually a tufa rock which is really only meant for Ciclid tanks. I have it in one of my tanks, but the PH in that tank is much lower. Still, it fixes the PH at a higher level than my other tank, which is stuck at 6.

 

[MeanHoney]

Sounds like the same rock - mine came from Petco too. As soon as I find a replacement for it, it'll come out.