HELP - Fluctuating pH during fishless cycle

[Cormag001]

Hello all,

I am currently in the process of cycling my first tank. It is a 37 gallon tank. The first week and a half of cycling went well -- I initially added the ammonia to 4ppm and took a test every day to track it. The ammonia started to drop and nitrites began to show up around a week in. While this was happening, my ph was consistently hovering from 6.6 to 6.8 (which is what my tap water reads) A few days ago, the ammonia started to drop rapidly. I was initially excited to see this, but now my pH is acting wacky.

Yesterday, my pH showed the lowest level possible on my test kit -- 6.0 ( and my ammonia at 0.25-0.5). The first day this happened I figured it was just a pH crash and did a 60% water change and added prime as well as ammonia to continue the cycling process. I bumped ammonia up to 3ppm and the new water ph was around 7.4.

Today, I woke up and the same thing had happened. My ammonia dropped to about 0.25 and my pH crashed to 6.0. This time it raised more red flags for me. I again performed a 50-60% water change, and immediately after the change my pH was around 6.4 (tap water is 6.6).

I dosed ammonia "halfway" up to 2ppm and recorded a pH of 7.2 after 30 minutes of the tank cycling. I then added ammonia to get the tank up closer to my "target" 4ppm. After letting it cycle another 30 minutes, my ammonia is at 3.5ppm and my pH has soared to 8.2!

What could be causing these massive fluctuations in ph? How harmful is it to my cycle? Should I stop adding ammonia until the water stabilizes?

 

[ZxC]

What substrate are you using?
What hardscape is in the tank?

I would invest in a kH liquid drop test, it's more important than pH.

 

[Cormag001]

What substrate are you using?
What hardscape is in the tank?

I would invest in a kH liquid drop test, it's more important than pH.

Sand. Here is a picture of the tank.

And okay, I will look into that. Any recommendations on brand?

 

[ZxC]

API liquid one. Get the combo kit that comes with the kH and gH test, it's useful as well.

I'm guessing your kH is low, close to zero, and you're ammonia / cycling situation is producing some acids or bases and causing the pH to swing without any buffer (kH acts as a pH buffer).

As of right now, keep on going with the cycling. Don't freak out over pH swings because you have no livestock to worry about at this point.

It could be simply CO2 built up in the water lines at your home, which won't hurt anything.

Look into a municipal water report too, and see if anything jumps out at you in terms of how they treat the water.

 

[Cormag001]

API liquid one. Get the combo kit that comes with the kH and gH test, it's useful as well.

I'm guessing your kH is low, close to zero, and you're ammonia / cycling situation is producing some acids or bases and causing the pH to swing without any buffer (kH acts as a pH buffer).

As of right now, keep on going with the cycling. Don't freak out over pH swings because you have no livestock to worry about at this point.

It could be simply CO2 built up in the water lines at your home, which won't hurt anything.

Look into a municipal water report too, and see if anything jumps out at you in terms of how they treat the water.

Thank you so much for the advice and for easing my mind a bit

I have ordered the test kits and will continue on with my cycling. When I get those kits and can get an idea for the water hardness I will report back.

 

[Cormag001]

So my hardness tests are on the way but I am concerned about the low pH stalling out the cycle. My nitrites / nitrates are still extremely high and it seems as if the ammonia is not disappearing as fast anymore. My pH is still reading at the lowest reading on the API test kit.

Any ideas on what to do?

 

[ZxC]

So my hardness tests are on the way but I am concerned about the low pH stalling out the cycle. My nitrites / nitrates are still extremely high and it seems as if the ammonia is not disappearing as fast anymore. My pH is still reading at the lowest reading on the API test kit.

Any ideas on what to do?

High NO2 / NO3 will stall the cycle.

Water change to keep the NO2 and NO3 lower, and continue to dose ammonia up to 2-4ppm.