pH level during Pure Ammonia Cycle

  • #1
Question: Should I do a partial water change to bring my pH level up?

Reason I ask: I have been conducting a fishless with pure ammonia cycle for 31 days. My Ammonia has fallen to 0 ppm three times in the past 12 days (each time I brought it back to roughly 4.0). My Nitrites are darker purple than my API master test kit can read. My Nitrates are about 10ppm. I recent lowered the temperature on the tank from 84 F to 76 F, A) to slow the rate of evaporation because tank was begining to emit a slight odor and I live in a small apartment, B) because tempertures near me have by in the high 90s-100s and I wanted to prevent the tank getting too warm and C) I finally got over NTS (I think) and come to terms with the fact that speeding the cycling process may not be the best idea. Now to the cusp on my problem. The pH in my tap water is 7.2. The pH in my tank has plummeted to between 6.0 and 6.4, but closer to 6.0. My understanding is having pH to close or lower than 6 can negatively affect my cycle. I was thinking that if I did a 50% water change, the pH in my tap water would help balance the current pH in my tank. Thoughts?
  • #2
PH Swings during Cycling are very normal. Nothing to worry about. As long as you don't have fish in there you don't need to worry too much about PH.
  • #3
+1 to Cichlidnut. You won't really be able to know what the pH will be in the tank until the cycling is done. And even then, most fish will acclimate to whatever pH you wind up with. What you want in the end is consistency, rather than chasing a number.
Good luck with your cycle.
  • #4
Welcome to Fishlore.

The goal of cycling is to process ammonia into nitrite and nitrite into nitrate. A tank is cycled when it can process at least 2 PPM ammonia into nitrate in less than 24 hours.

As your nitrite levels are off the scale and as you have nitrate, I would do a 50% water change. When levels become too excessive, in your case the nitrites, it can actually burn the bacteria and slow down the cycling process. This water change would be to reduce nitrites, not to correct any perceived pH issue.

I would also run all nitrogen parameters on your untreated tap water. If your tap has 0 nitrate then you know that your tank is starting to convert nitrites and you are very close to completing the cycle.
  • #5
Good morning,

The 50% water change should help to increase your pH levels too. Once the pH drops below 7.0, it may slow the cycling but it will not prevent the tank from cycling. If the pH falls below 6.0 then any beneficial bacteria that may be developing, may begin to go dormant.

Please do not use any chemicals to alter your pH levels. They are unstable and can lead to a pH crash.

Since you are cycling fishless, the warmer water will help to speed up the cycling process. I would try and avoid going over 86 degrees.

  • #6
Yes you are almost there, the pH as ken mentioned are spot on, because and only because this is a fish less cycle if the pH falls to far and water changes are not bringing it up then I would add a natural alkalinity buffer such as baking soda, very trace amounts will do the job and kick the bacteria over for you. Again that is only if it really starts to fall below 6 and your water changes are not making it move up at all.

Other than that it looks like your on a nice track for a great tank.
  • Thread Starter
  • #7
This is my first time checking this forum since July 4 because I wa sout of town on vacation. I boosted the Ammonia level in my tank to 6ppm to keep the bacteria working while I was gone. I got home last night and the ammonia level in my tank was still around 4ppm which means my cycle stalled. I did not check my pH, but can only imagine that its still well below 7. I will do a 75% water change tonight as soon as I get home form work.

2 side note. 1) I've heard that brown algae is a good sign of cycling. I came home to the sight of brown algae growing on the black (top) part of my water heater. Should I clean it when I do my water change? 2) Yesterday the strangest thing happened with my API master test kit. When I got home I tested Ammonia levels, Nitrite levels, and Nitrate Levels. My Nitrite results seemed odd. Basically I ran the test and left it to sit for 5 minutes. Well my wife called my attention away and I don't know how longI let it sit, but when I finally got back to it, it read 0ppm, even though the ammonia read 4ppm. It left me scratching my head because I had a nitrite spike nearly 3 weeks ago. So I re-tesed the water for nitrites and checked on it at exactly 5 minutes. This time it showed my nitrites were somewhere past 4ppm. Is this a common occurnence?
  • Thread Starter
  • #8
I decided to do a 50% water change and not clean off the brown algae. The WC brought my ammonia down to 2ppm, but my nitrites are still atleast 3-4ppm. I did not add more ammonia. I plan to wait until it drop to 0. pH back up around 7.0.

Still don't know what's was going on with that Nitrite tes tthat showed 0ppm.
  • #9
Good morning,

It's a good possibility that with the Ammonia level above 4.0 it caused the cycle to stall. Once it goes above 4.0 the beneficial bacteria may not be able to catch up and get it all processed. Try and keep it below 4.0 when using pure ammonia.


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