Low pH?

[Karackle]

I was doing my bi-weekly water change on my well established 20g tank and decided it had been a while since I did water parameter checks so i figured I'd do them. The ammonia, nitrIte and nitrAte were all normal (0, 0, 10-15) but the pH was unusually low, it was 6.0. I never recalled my pH being that low, but since memories can lie to us, i figured i'd check some other things. So I checked my 5g tank, pH there was ~6.8, and the water coming out of my tap is 7.8+ (my drops only read to 7.8, the water was blue which is over 7.8 but who's to say how much.)

So my question is threefold:

1) What causes the pH to drop?

2) Should I worry about it / do something to try and bring it back up?

3) Could the low pH have caused the problem with intestinal parasites I recently had?

Thanks in advance!!!

Tank Parameters:
20g High, planted, low tech tank
regular aquarium gravel, 78 degrees, Penguin Biowheel 100 filter
Flora:
Purple Cabomba, Wisteria, Cryptocoryne wendtii red (small), Crypt wendtii green (large), Crypt spiralis, Anubias (nana i think)
Fauna:
3 female Bettas, 3 mollies, 3 neon tetras, 3 glolight tetras, 3 zebra danios, 1 female guppy, 1 clown pleco

5.5 Gallon, planted, low tech
regular aquarium gravel, 80 degrees, Red Sea nano filter
Flora:
Purple cabomba, wisteria, Crypt wendtii Red (large and small), crypt w. green, anubias (again, nana i think).
Fauna:1 male betta, 2 otos

 

[Fishyfanatic]

How long has the tank been set up?

 

[Purrbox]

Is there any driftwood in either aquarium?

 

[Karackle]

Tank's been set up for about 2 years. There is a piece of malaysian driftwood in the 20g and a small piece of some other kind of whiter, lightweight driftwood in the 5.5g, both tanks have had the driftwood in them for 3+ months.

 

[Purrbox]

The tanins released by driftwood will lower the pH. As will built up detris in the substrate.

 

[Fishyfanatic]

As Joy mentioned it could be a combinatino of the driftwood and old tank syndrome. Do you perform deep gravel vacs? What kind of filtration are you running?

 

[Karackle]

Yes, i gravel vac every time, or every other time I do a water change (ever 2 or 3 weeks) depending on what the top of the substrate looks like. I should have mentioned the tank has been up for 2 years, but, about 7 months ago i doubled the volume of the gravel (added black to the blue and purple) and slowly switched it over to a planted tank, so it shouldn't be suffering too much from old tank syndrome i don't think(you can see my journal here http://www.aquariumadvice.com/forums/f19/my-20g-planted-journal-56k-101691.html)

It could be the driftwood though, i hadn't thought of that, the water cleared of tannins a while ago, but could it still be from the wood? If so, what should I do (if anything) to raise the pH?

Also, the 5 gallon is a younger tank, only about 4-5 months old, should I worry about the pH in that tank? it's 6.8.

As always, thanks so much for the advice!!!

 

[Purrbox]

Your pH is fine as long it's stable (even if lower than expected) and should be left alone. If it's continuing to move or fluctuating, you would want to consider buffering the KH to stabilize it.

 

[Karackle]

great thanks! I'll just do more regular test now that I know it's on the low side to make sure that it's stable! Thanks again for the advice!!!

 

[CompMage]

I had the same problem. I moved from simple gravel to mostly eco-complete and it fixed my problem. My PH was also around 6 and the tap was right around 7.4. My KH was low.

Once I added the eco, everything seemed to stablize for me. And the plants loved it!

 

[Karackle]

good to know! Thanks for the advice!