ph jumps

[Skittyfish]

My ph from my tap is 6.6-6.8 in both of my aquariums the ph is 7.2-7.4. Anyone know what would cause it to jump so high? I did about a 40% water change last night, and the ph is still 7.4. I don't have my kh test kit yet (should be here in a day or 2.)
I have 0 ammonia in both tanks. There is a large piece of driftwood in the 72 and a couple of clay pots and two small pieces of slate.

[NJ Devils Fan]

I put this piece of wood in my tank a few days ago and it brought the ph down from around 7.6 to 7.0, so I wonder what would make it jump like that.
http://pic4.picturetrail.com/VOL47/889630/1620657/19028139.jpg

[Skittyfish]

Thats a nice piece. Someday I am going to take a pic and figure out how to get it on here. Anyway, my driftwood has been in the tank for nearly a year now ( i just ordered two smaller ones this morning). I added 110 oz. of pure laterite to my gravel yesterday, but the ph didn't change from that (I didn't put any in my 10). Also, my 10 g doesn't have any wood in it, just a resin look-a-like. The only thing I can figure is that the rain and snow going into the lake that our water comes from is causing the ph to be lower from the tap. When I find out my kh I will post it.

[wetmanNY]

Perhaps you'd give us the pH of your tapwater as it comes from the tap and also as it is after standing overnight in a glass. Difference suggest the effects of carbon dioxide in lightly buffered water.

The pH can rise because of added carbonates, most likely from the kind of gravel you're using. (Or from photosynthesis, orfrom lowered CO2.)

"I added 110 oz. of pure laterite to my gravel yesterday, but the ph didn't change from that"
Very odd statement. Incomprehensible, really...

When you have a pH test kit, you'll be able to do a before-and-after test I guess...

[Cichlid Woman]

That's true, the pH on water out of the tap can change significantly after sitting a day, in your tank or out. Also--any chance your substrate is hiking the pH up?

-- Pat

[Skittyfish]

I don't think so, the only thing in there is estes gravel walnut color. I put the laterite in yesterday in the 72. But the 10g has the same ph as the 72 and it only has the gravel. I'll be sure and post my test results as soon as I get the new test kits. The only test's I have right now is ammonia and ph. I'll also set a cup of water out and test it tomorrow.

[wetmanNY]

I have a tank with a mix that includes Estes Bits o' Walnut epoxy-coated aggregate gravel. Completely inert. So that's out.

We're figuring that these are unplanted tanks or you would have said something.

[Skittyfish]

O.k. I left a cup of water out over night, and the ph out of the tap is 6.6-6.8 after 16 hours it is 7.2-7.4.

There are 3 java ferns, an A.ulvaceus, two crypts, and another plant that kind of looks like an onion.
There are 2 pictus cats, 3 otocinclus, 6 serpae tetras,1 green cory, and one head and tail light tetra (can't catch him).

I have an eheim 2026 with the ehfimech, and ehfisubstrat, and the fine and coarse filters. I also use occasionally a magnum HOT with the micron filter after a thorough cleaning.

Thats about it.
Thanks!:)

[wetmanNY]

Mystery solved! Your buffer must be light (soon you'll be doing a KH test), which makes the pH flexible. CO2 in the water depresses the pH. So your tapwater has elevated levels of CO2 typical of water that has leached through an aquifer, and CO2 diffusing in from the atmosphere is enough to raise the pH to 7.2 - 7.4 in the course of a day.

(edit) I got the italicized part backwards; someone should have hit the gong! Rising pH, means lowering CO2. The tapwater sounds like it's supercharged with CO2 as it come from the tap.

Ideal water for most kinds of fish!

[Skittyfish]

Yippee! Test kit came and heres what I got

Hagen Test kits...

GH is 100ppm or 5.6gh Degrees
KH is 40 ppm or 2.24 kh degrees

ph is 7.4 or 7.6 can't really tell the color well
nitrate is 5
phosphate is 0
Ammonia is 0
that is all I have tested for so far. I can do Iron, Calcium, nitrite also.

Now somebody tell me what all of this means Please:confused:

[djlen]

You have very low kH, which buffers stabalizes your pH and probably have an elevated level of CO2 in your tap water, which causes it to be low when it comes out of your tap. As it sits overnight the CO2 "gases out" and the pH rises. Not a big deal. I wouldn't worry about it unless you decide to get fish that like a really really acidic water. Most fish will do fine in the water parameters you describe. And if you're like the rest of us nuts, you'll probably eventually go crazy and want to add CO2 to your tank and the pH will come down again. Once again, don't worry about it....my kH is 2 as well and it'll be ok.
Len