PH creeping upward

[jokerfac]

Over the past week, my PH has been slowly creeping upward. My PH on 18 June 2003 started at 8.0. It had been stable for several weeks. Since then, I added 3 zebra danios and my plants have been growing very well. It has been creeping upward about 0.1 per day. On 22 June 2003, I did a 10% water change which stablized it for that day. Also, it seems to changing 0.4 PH per day when measuring before the lights come on and after the lights turn off. What should I do?

I know that a PH of 8.0 was high for the zebra danios, but LFS keeps their tanks at 7.8 for zebra danios. I did not want to add anything to the water because I was hoping to keep the PH stable even if it was high nor add phosphates for fear of algae growth.

Did fishless cycle before adding fish for one month. Did 25% water change after finishing.

Water parameters and other info:
20g tank
3 zebra danios
lots of plants
PH 8.3
Nitrites 0.0
Nitrates 0.0
Ammonia 0.0
KH 8 dH
GH 8 dH

 

[Biggen]

Do you have any kind of materials (rocks, corals, sand, etc...) that could possible cause the pH level to rise? What kind of gravel and other ornaments?

Do you inject Co2 into the water? Judging by that pH I would say you don't, but I want to make sure. Injecting Co2 would help bring your pH level down to a more neutral level...

I actually wish I had your pH. Would be great for African Cichlids. My pH for my tanks will go below 6.2 if I let it. No kH here.

 

[jokerfac]

No, I do not have any rocks that would cause the PH to rise. The gravel is the standard aquarium gravel from Petsmart. My PH was stable for a month during the fishless cycle.

I do not inject C02 into the water. What would be the best method for injecting C02? I saw postings about the Hagen kit and equipment for CO2 injecting.

Yeah, my water would be great for African Cichlids, but I wanted to start with beginner fish since it has been about 10 years since I kept a tank. In MN, it was a lot easier because our water parameters were about perfect when I lived there.

 

[loganj]

It depends on what kind of fish you want to keep. Danios will do well in a wide range of pH. One thing you might do is to mix distilled water with your tap water to achieve the desired pH and hardness. With a KH of 8, your water isn't all that hard. Have you noticed any white calcerous deposits on the leaves of any of the plants? Your C02 is pretty low at about 2 m/L. It needs to be at least 10 for the plants. What may be happening is a process called biogenic decalcification where the plants, starving for C02, split off the hydrogen carbonates and break them down into C02 and carbonates. As a result, pH can rise as much as one point. Then, at night when photosynthesis is not possible, the process reverses to an extent and hydrogen carbonates are reformed, although not at the same rate they were broken down. The net result is a increase in pH over a period of time. My first thought is that you may want to go with a combination of distilled/tap water mix and C02 injection. Cutting down on surface turbulence will help keep C02 dissolved also.

 

[jokerfac]

No, there aren't any white calcerous deposits on my plants. I am planning on adding more danios, cories and some otos or SAEs over the next few months, but I want to get this problem solved before I add any more fish. I will try what Logan and Biggen suggested. Thanks for the prompt advice. I love all the information I get from these forums.

 

[loganj]

You might try to find a copy of "Aquarium Plants Manual" by Ines Scheurmann. It's a small paperback that is loaded with info on different plants and has great info on C02 and water chemistry. I paid about $8.00 for it several years ago. It's part of the Barron's Premium Pet Care series.
Barron's Educational Series, Inc.
250 Wireless Blvd
Hauppauge, NY 11788
1-800-645-3476
I think you'd find it worthwhile reading if you're going to keep plants.