How to stabilize pH?

[FoundMoney]

My tank seems to fluctuate in pH. Tap water is around 6.8 and I do weekly water changes. However after a week the pH in the tank can rise to as high as 7.6. How can I stabilize this without adding chemicals or spending too much on equipment? Should I just change the water more often?

 

[B75]

I used to have this problem with my first tank. All I did was add a piece of bogwood and this brought the ph down slightly and stabalised it.

 

[FoundMoney]

Nice suggestion but I have three pieces of bogwood in my tank.

 

[freddyk]

Fill a container with tap water and measure the ph. Then run an airstone in it over night and measure it again. Did it rise? If so, the reason is that as the water is aerated through filters and perhaps air pumps, oxygen is obsorbed while carbon dioxide is dissipated. This tends to cause a rise in ph. It's a worthwhile experiment, because if this is the reason you don't need to do anything - it's normal.

 

[FoundMoney]

I will give that a try. This makes a lot of sense but wouldn't it mean that in most aquariums the pH will rise? It may be normal but how do fishkeepers maintain a stable envirnoment for the fish? To be sure, the fluctions in pH are not huge - they go from slightly acidic to slightly basic, but still wouldn't this stress fish a bit? Perhaps these small fluctuations are so gradual that the fish aren't affected.

 

[freddyk]

Not everyone's tap water is the same, so people get different results. What I mention is a tendancy, but it doesn't always work like that. Water with less Co2 in it will show less fluctuation. The change is not as much as you may think, since you're only doing a partial water change, the ph would drop only slightly, and the fish can handle slight changes.

 

[nc_nutcase]

So do I understand this correctly that adding bubbles (aeration) to my tank will raise the PH?

are there any other little tips such as this I can use?

Also what little things that we commonly do (or uncommonly even) will lower PH? This way I can avoid such things (except bog wood... gotta have tht )

 

[rdd1952]

Does adding ammonia during the cycling period also raise pH? I checked mine yesterday on the cycling tank (just put the substrate and water in on Saturday evening) and it was off the chart. I checked High pH and it was at 8.4. My normal tap water is 6.8 to 7.0 and my tanks generaly run 6.6 to 6.8.

 

[FoundMoney]

Adding bubbles (oxygen) to the tank can raise pH as it can displace CO2. CO2 in water will create a weak carbonic acid (I think) so displacing CO2 will cause pH to go up.

Ammonia is a strong base so adding it to the tank should definitely raise pH.

 

[nc_nutcase]

is it possible that I over clean my tank and therefore my Ammonia levels are low which lowers my PH?

I do larger than typically recommended water changes on a weekly basis 25-30%). I use a 350 GPH canister filter (Magnum 350) w/ a 20 W UV light on a 125 gal tank.

 

[FoundMoney]

I'm starting to get over my head now in terms of water chemistry but I don't think the absence of ammonia will lower pH, only that excess ammonia will raise it. Pure water is neutral 7.0 so taking out ammonia can't lower the pH of water. There must be another source of acid in the water to lower pH.

 

[nc_nutcase]

so now your saying my fish are on acid?

do they make fish rehabs???

 

[Nidge]

What substrate have you got in your tank? This can have a huge effect on ph.

 

[FoundMoney]

Mine is a fine gravel mixed with laterite on the bottom with a larger darker gravel on top.