Why does my pH keep rising?

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Rocket2001

Aquarium Advice Freak
Joined
Aug 25, 2004
Messages
369
Location
Massachusetts
My tank is just about fully cycled. Its been set-up for six weeks and is slightly over stocked. Through out my cycle I've never had any problems with the water parameters. The numbers did what they were suppose to at each stage of the cycle and now ammonia is almost zero, nitrites are zero and nitrates are 20 ppm. The only concern I had was water temp during a couple of hot spells in Aug. other than that the only problem has been pH..it has risen to 7.8 a couple of weeks back and I treated it with Bullseye 7.0 (pH regulator) It dropped to 7.2 then rose to 7.6 again. I treated with Bullseye agin and it went back down to 7.2..now its at 7.8 again....Why? and what can I do to correct the problems.
Notes: Community tank
Artificial plants
small fish 1-3 in
 
are you doing frequent water changes? Sometimes, if you do a large water change and the CO2 concentration in the tap is high, the pH will rise as the CO2 equilibrates with the atmosphere. This can be diminished by having a good buffering capacity in your water. What's your KH? Having a KH above 4-5 is important to keep from having big pH swings. If it's low you can bring it up by filtering crushed coral.

Unfortunately crushed coral will bring your pH up a slight bit, but prob not like the bump you're seeing. If the crushed coral does raise your pH too much, you can add some bogwood to your tank or cofilter with peat. This will allow you to bring up the KH with the coral while keeping your pH relatively stable.

Also, if you have plants, injecting CO2 will also bring down your pH while stimulating plant growth.
 
Do not use chemicals to treat pH!! If your water is not well buffered (and it's not), there will be swings in pH and your fish will become stressed.
Your fish will probably be fine with a pH of 7.8, but if you REALLY want to lower it, do it the natural way with natural wood or add peat moss to your filter.
 
Menagerie do you agree with Treedae about adding live plants that will lower pH? It havs been my thought that i will replace the fake plants with live ones once my tank has finished cycling (i am about there). i'm a bit hesitant about the bogwood or peat because I've read that it tints the water brown and I've been very lucky to have a crystal clear tank..I'd like to keep it that way. Also what is "well buffered water"?

I've done two 25% water changes over the last 6 weeks. A test showed my tap water to be 7.0 pH
 
I think you misunderstood. adding plants won't lower your pH. In fact, it will likley raise the pH b/c of the consumption of CO2. It's the addition of CO2 through a CO2 injector that will lower your pH.

Before you do anything, you need to get your KH up so see where it is and take it from there.

Buffering is what's going to happen when you get your KH up. KH is a measure of certain salts in your water (Calcium and Magnesium Carbonate salts specifically) They dissolve as bicarbonate ions (HCO3-) and the more of this you have available, the more CO2 you will have "stored" in your tank (because H + HCO3 <--> H2O + CO2) to act as a reservoir for H ions.
 
Also, if you have plants, injecting CO2 will also bring down your pH while stimulating plant growth.
The CO2 will do it, not the plants.
As a tank ages, even with water changes, the pH naturally goes down a bit.

Some water is not buffered, which means when you add the chemicals, the pH does what you want, but can't stay there. treedae has given an excellent explaination--kudos to you, treedae!! My chemistry isn't on the ball anymore :oops:
 
Your tank is still very new Rocket2001. As your tank ages you will see the PH gradually fall on its own. It's the natural result of waste being produced by your fish and all that good bacteria your filters have established.

But in total agreement with Menagerie and treedae, you need to get a handle on the KH to avoid swings in PH. As surely as your PH is rising now, it will spike in the reverse direction if you don't. Adding products like bullseye to alter PH will only increase the swings if your water isn't buffered. I've had great success using crushed coral.
 
Ok, I think I understand whats been said here and now that I've been thinking about it I have had another problem that may have been related... Brown Algae I was having a problem with it covering the decorations, plants and gravel. I cleaned it off and it just came back...so on advice I got 3 otto cats and they did a great job cleaning it. (maybe they just treated a symtom). It is my understanding that O2/CO2 exchange could cause Brown Algae. Is it possible I am not agitating surface water enough to allow proper exchange. I have a Fluval 303 Canister Filter and use the spray bar tilted upward to ripple the surface water. I think this is OK but now I'm not so sure.

What are your thoughts on this possible problem..could the high pH and the brown algae be related?
 
Not at all Rocket. Diatom (brown) algae usually appear before any of the green algae. It feeds on the nutrients in your water column and is bolstered by whatever light is present. Try reducing the hours you leave your light on and see if this helps.
 
I'd suggest testing the KH and GH levels of your tap water to see exactly what you're working with from the beginning. It's possible that your water does have a high buffering capacity, which would explain why the chemical "fix" is only temporary.
 
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