Confused On My Cycling Progress

[koinukun]

Hello everyone! Yet another fishless cycling question being asked, sorry but I'm totally confused!

I have been cycling my 155L tank for over 3 weeks now and the cycle was a text book case, ammonia drops, I add more, nitites appear then nitrates, nitrites disappear over night etc. Now I'm experiencing some hiccups. For some reason my ammonia isn't processing all that fast. When it reaches about under 1ppm I put it up to about 3/4 ppm and only goes down around 1ppm a day.

Another weird thing that happened was the pH in my tank. My tapwater is pH7, usually the water in the tank is around 7-7.2, but right after my nitrites disappeared overnight the pH was 6! I guessed this to be the reason for the slowness of the bacteria as they go dormant if the pH is too acidic. I did about a 50% water change with dechlorinator and put some stuff in to raise the pH so now the pH in my tank is about 7.4 but the ammonia is still really slow in going down.

I thought once the nitrites had gone over night I was on my way but this has made me wanna hold off putting in fish and ask you guys for some advice as to what is going on and should I wait like another week for things to calm down?

Thank you for any input you can give!

koinukun~

 

[Miss Wiggle]

The low pH will affect your cycle, the lower it is the slower the bacteria grow and therefore the slower your tank processes ammonia. Is the reading of 6 the lowest reading on your test kit or does it go lower? The reason I ask is if your reading is the lowest on the kit then it may actually be lower than 6. If it drops below 5.5 the bacteria you’ve worked so hard to grow may die off and you have to start again, so it’s important to be sure of exactly how low it drops if it does it again.

However the fact that once you have raised the pH the tank is still processing ammonia reassures me that all the bacteria are not dead, however what has happened is that your tanks cycling process has effectively been set back a few days and the bacteria need to grow back to where they were before the pH dropped.

Monitor your pH for the next few days, make sure it doesn’t drop again, hopefully the cycle will get back to where you were in a couple of days time, you may find that you’re set back a bit and that you have another week or so of cycling to go. Unfortunate but cycling isn’t always plain sailing.

 

[rdd1952]

I agree that the pH drop is slowing the process. At lower pH levels, the bacteria that are present will continue to process ammonia but just reproduce very slowly (or not at all if the pH gets too low) so the colony isn't growing. I would suggest doing a massive water chage (75 to 90 percent) to get the pH back up close to he ap pH of 7. This will allow reproduction to pick up again. It will also get the chemical that you added to raise the pH back out of the tank (if there is any portion of it left). I guess they are ok during cycling bu s a general rule, you want to avoid pH adjusters like the plague as they can cause too many swings and fluctuations in you pH. Don't worry about the nitrite that you will be removing as there will still be some left (from the 10 to 25 percent of the water you didn't change) and of course the ammonia you add back in will quickly be processed into nitrite.

Have you tested the GH and KH of your tap water? The sudden drop in your pH is most likely a result of the cycling process but it probably also means you have no buffering capacity which will be something you need to be aware of once your tank is cycled and you start adding fish. The addition of certain items like driftwood (lowers pH) or certain rocks (limestone rocks will raise pH) can cause big swings when you have no buffering capacity.

 

[koinukun]

Thanks for your replies!

I got up this morning to find my pH back to 6 or below again within 24 hours! (my pH test only goes down to 6 so I'm guessing it could be lower. I can't get another test kit yet though because I can't get to a LFS until next week or so ) The levels of ammonia had gone down slightly over night so not all of them are dead thank god!

I did what you suggested and did a large 90% water change which raised my pH back to 7 and got rid of my ammonia and nitrite levels. Then I though I may as well start from the beginning so I added enough ammonia to raise it to 6pmm.

How can I keep the pH a constant 7 without a raise pH formula? Do I just need to water change often?

I don't really understand GH and KH and I don't have a test kit for them. Can you buy them just like ammonia test kits and such?

If that's the problem how can I overcome it?

I don't think the decor in my tank would be the culprit. I have 2 bits of fake driftwood, a piece of lava rock, I have another 2 kinds of rock but I don't know what they are, I just bought them from the petshop. Ones a pinky red and white marbled looking one and the other full of holes and is a grey brown.

Thanks so much for the help! I'm a bit upset that it was all going so well and has completely gone down hill but hopefully it will be alright...

koinukun~

 

[koinukun]

Well I've done some research on water chemistry and the relationship between pH and water hardness and softness.
Do you think the pH drop could be a cause from me adding CO2 to the tank for my plants?

I have a DIY CO2 reactor with the 2L softdrink bottle and the yeast and sugar mix with a diffuser head in the tank. Could this be what's causing the erratic behaviour if my water is soft? Looking back at my cycle diary, the time I added the CO2 was around about the time the ammonia slowed down.

I will get a gH/kH test kit when I next go to the LFS.

koinukun~

 

[rdd1952]

CO2 can definitely reduce pH. The more CO2 in the water, the lower the pH. I'm not certain how much CO2 you are adding. How many bubbles per minute are you getting? There is information on the internet about how many bubbles per minute you need and the effects. I will try to find it or you can do a Google search. Also, are you turning the CO2 off at night whe the lights go off? If not, that is probably your problem. When the lighs are off, plants don't use the CO2 nearly as fast so it can build in the water and push the pH down. That could be the reason you are seeing the big drop overnight.

As for your GH/KH, I would suspect that they are very low. That's not necessarily a problem as mine are both 0 and I am able to maintain my tanks without any problem and have driftwood (which will lower pH some) in both. I think you wil be fine once you get the CO2 regulated properly. To raise the pH naturally, you can add a small amount (probably only need a teaspoonful or so) of crushed coral to the filter or place a small piece of tufa rock in the tank. Both will add buffering capacity and help raise the pH and keep it steady.