[helmuthead]

Hi guys and gals. I had fresh water tanks growing up and recently decided to buy another setup. I have a 30 gallon tank with all new equipment. I set my tank up and waited about 3 days and began buying live plants getting everything set for the fish. i checked my ph the first day and all was well. About a week in i check it and it has spiked very high. The water was clear and the plants looked good but the ph was pushing 7.8 or higher. I do a partial change and use a ph down tablet that worked for about one day. I eventually tear the tank down in frustration and move the plants to a stable backup tank. I clean everything and give the aquarium 2 days to settle with NOTHING but an empty tank. I also keep 5 gallons in a clean bucket separate from everything... so low and behold 2 days later the PH has spiked again with nothing in the tank? I check the bucket i quarantined and guess what... the ph is spiked the same as the fish tank... what the heck is going on? :fishGreen:

 

[Dmaaaaax]

My guess is that your tap is very soft. Soft water (kH 1-2) can fluctuate very easily with the smallest change in chemicals. For instance if you lose the CO2 in the tank by natural gassing off due to water movement, the pH will go up.

You never said what your pH was at to begin with so I am not sure how much of a swing you are getting or what pH you are trying to achieve, but the easiest way to keep it from spiking or dipping is to buffer it. This means adding an acid and akaline buffer to get to a specific target pH.

I use acid and akaline buffer from Seachem. By adding x amount of the akaline buffer I can raise my kH to whatever I want. I shoot for 3-4. Then I add acid buffer until I get to my desired pH. Now every time I do a water change I just add a known amount of both.

 

[helmuthead]

The tap starts at 7.2 -7.4 range and ends up at 7.8 ++ within one day.

 

[Dmaaaaax]

My guess is loss of CO2. Try this:

Get water from your tap and put it into 2 test tubes. Test one normally, and for the other one...cap it and shake it vigorously for a min then test it. If it is CO2, the shaking would have gotten rid of it, and your pH should be higher in that tube.

If you can sometime, take your water to a fish store and have them test the kH and GH.