pH problems

[RoopeB]

I have a quite new tank, recently cycled. At first the pH changed from 7,5 to 8. Higher at days, lower at nights. Gh5 Kh3. There isn't any such decomaterial in that would increase the pH, so I took tap water in a bucket and it rose in 24h to near pH8. So it is the water it self i think.

Ok fine I thought and bought a Co2 system few days ago. Plugged it on around midday and measured the pH in couple of hours. I was pleased with the results. Waited couple of more hours and measured again, it was slowly dropping. I was happy. The night came and I swiched Co2 off, since I thought the plants arent able to use Co2 at night because of the lights. Co2 went off at 8pm and I measured the water after few hour. Poop, it is going higher again. Again after two hours did the measurement again, still rising. This morning around 10am my pH was around 7,7 so I put the Co2 back on.

24.07.2009
12:00 Co2 on ph7,45 - 14:00 ph7,37 - 15:00 ph7,3 - 16:00 ph7,25 - 19:00 ph7,12 - 20:00 Co2 system off - 21:00 ph7,2 - 22:00 ph7,25 - 0:55 ph7,4

25.07.2009
11:00 Co2 sytem back on ph7,62 - 12:00 ph7,45

If I increase my current Kh3, it might buffer pH better but will also increase the pH some, so I'd have even more fight to battle to get it down. Do you guys have any suggestions? I'm about to house an young p. motoro in future in this tank.

Some previous test results, without Co2 system:

21.07.2009
10:00 ph7,57 - 12:00 ph7,64 - 15:00 ph7,85 - 16:00 ph7,9 - 18:00 ph7,98 - 20:00 (lights off) ph7,97 - 22:30 ph7,83 - 24:00 ph7,75 - 02:30 ph7,67

22.07.2009
10:30 ph7,73 - 13:00 ph7,73 - 15:00 ph7,73

23.07.2009
11:30 ph7,7 - 13:00 ph7,77 - 14:00 ph7,74 - 20:30 ph7,94

 

[RoopeB]

I measured Gh and Kh again: 25.07.2009, 12:40 Gh6 Kh4

for comparision: 23.07.2009, Gh5 Kh3 - at the evening 40% waterchange

 

[ashleysomething]

What is your tank made of? There could be an impurity in the building materials. Zoodiver talked about this on a previous post (if I am not mistaken); cement, for instance, can jack up your pH.

One suggestion that I have is that you move the inhabitants and install a drip system until the pH settles down. Alternatively, you could coat any questionable surfaces with pondarmor or something similar. Best of luck.

 

[ShadowStryder]

Does it stablize at its highest point? Or does it constantly fluctuate? If it is stable
at the higher PH I would let it stay there and not worry about trying to adjust with
chemicals.
My PH runs consistantly at 7.8, I don't try to adjust it in any way. My Motoros don't
have any issues with it.
The more you try to adjust it causing constant fluctuations is more detrimental to the
rays than a high but stable PH.

 

[Deaths Sting]

Does it stablize at its highest point? Or does it constantly fluctuate? If it is stable
at the higher PH I would let it stay there and not worry about trying to adjust with
chemicals.
My PH runs consistantly at 7.8, I don't try to adjust it in any way. My Motoros don't
have any issues with it.
The more you try to adjust it causing constant fluctuations is more detrimental to the
rays than a high but stable PH.

+1

i use to have 0 KH and my ph would be fluctuating non stop. crushed coral solved all my problems, my KH is now 120ppm and my ph is stable at around 7.6 - 7.8

like said before me, its better to have high but stable Ph then low fluctuating Ph.

 

[RoopeB]

The tank is completely made out of glass and the only decorations I have in are some wood and few (echinodorus sp.) plants. I ran a test in past, put sand in a bucket and filled it up with tap water. The Ph rose up to pH8 in a day. So the problem is not the sand either, I think.

My pH fluctuates as decribed in the fist post. At day time it will rise to pH8 and falls to pH7,4-7,6 at night. This was before adding the Co2 system. With added Co2 the pH is at day time around pH7,1 and rises to pH7,7-7,8 at nights. Co2 goes off at 8pm along with the lights.

Gh6 Kh4

 

[RoopeB]

I will follow the pH for a few days and keep track on the measurements. I'll see what happens and how much it fluctuates.