ph Question

[jersysman]

am in the process of cycling a 20 gallon tank. It has been 6 days now and the ammonia is at 8 ppm. My question is about pH though. I tested the pH in the aquarium and it registered 8.0. I then tested the pH of my tap water and it was 7.4. Does the cycling process raise the pH of the water? Or, could it be the gravel? It's just regular gravel I got from the LFS. I want to have some rainbows in my tank and a pH reading of 8.0 is too high for them, while the 7.4 would be okay. Should I expect a drop in pH after the tank is cycled?

 

[Essayons89]

Base chemicals release hydroxide ions into the water, since ammonia is a weak base it can raise the pH of your tank water. You may or may not see the pH drop a bit when the cycle is finished. Regular aquarium gravel is inert and shouldn't alter the water chemistry at all.

Bryan

 

[RoK]

I think the pH of tap water when you test it right away will usually be lower than when you leave it out awhile. Not totally sure though.

 

[Essayons89]

I think the pH of tap water when you test it right away will usually be lower than when you leave it out awhile. Not totally sure though.

Mine is always the same after I let it gas out. Jerseyman, you can test this by setting out a cup of dechlored tap water for 24 hours to let the co2 gas out before testing. This will give you a truer reading of what your pH, kH and gH is.

PH levels can vary during cycling. I think that the pH will be at its highest during the ammonia phase of the cycle because ammonia is an alkali. This will cause the pH to rise.

Bryan

 

[jersysman]

Thanks for the replies. I'll test it again after the ammonia levels drop and see what I get. I just don't want it too high so that I can keep the rainbow fish. However, this summer when I get my 75 I want it high for the african cichlids. <sigh>

 

[Nautilus]

Jersyman, even if you are doing fishless cycle, the 8 ppm of Ammonia is still too high for the bacteria to grow. Make it approximately 5 ppm. Then, depending what kind of ammonia do you use, check PH regularly. It may crash soon, which is also not good for bacteria. If PH drops too low, regulate it with baking soda.

 

[Essayons89]

Good points Nautilus.

When doing a fishless cycle you need to add enough ammonia in the beginning to bring the level to 5ppm then only add enough to maintain this until the ammonia falls and you see a noticeable increase in nitrite. Once the ammonia falls to 0ppm and you have nitrite you only need to add enough ammonia to maintain 1ppm until the nitrite falls to 0ppm and you have nitrates. The nitrates can be very high at the end of a fishless cycle, water changes will bring them down before adding fish. Ideally you want them around 5-10ppm.

Bryan

 

[Fishyfanatic]

it approximately 5 ppm.

Actually, I have read and from experience, have noticed that a tank will cycle faster at an ammonia rate of 1 ppm. That is as long as it is a fishless cycle. Are you using fish to cycle your tank?

 

[malkore]

ammonia levels over 5ppm will harm the bacteria, so 8ppm is too high.
ammonia can increase pH since it's a base.
Best thing to do is get a Kh test kit, and see if you don't have a lot of carbonate hardness. Kh and pH are linked. High Kh will raise pH, and buffer against changes to pH.

 

[jersysman]

Thanks for all the help. I'll do a water change to bring down the ammonia level. I keep everyone posted. This is the kind of help I needed.

 

[Fishyfanatic]

Jerseysman, where in IL are you from?