Im confused :/

[Jujubee]

I have a 20 gal long that's really confusing me. It was cycled with 3 baby platys. After the tank cycled I added my beta with the babies, everyone gets along. But my water has been doing weird things. I have a filter I had in my 10 gal which was cycled several months ago. For a few days the 20 was fine, I did a deep gravel clean with 50-90% water change to bring nitrates down. Now today my water had .50 ammonia .25 nitrite and off the chart nitrates.
The tank it self had cycled before I added my 10 gal filter and I did not take anything out of the 20. It is planted and yes, there were a few dead leaves and I did a big trimming. I also uprooted and moved some of the plants around.

What could be causing this to happen? I have 2 other tanks, 10 & 30 that are doing awesome. I'm really confused and worried, I leave tomorrow afternoon to go back home for 10 days with my husband. It's an 8 hour drive :O

I just did a small water change and will do a 50% in an hr or two and then another bigger, 80-90% tonight to drop everything down. I'm scared it will all rise and be thrown off tomorrow.

 

[threnjen]

Mini cycle? There must have just been a lot of gunk in the gravel maybe?

 

[Mebbid]

Mini cycle? There must have just been a lot of gunk in the gravel maybe?

Im going to agree with this. Gravel collects a ton of debris and disturbing it as much as you did can cause issues like that. It's the reason a lot of us use sand.

Another thing I would point out, its generally a bad idea to do more than a 50% change.

 

[Jujubee]

Oh dang :/ there was a lot In the gravel hence why I did such a clean. My tank is rather heavily planted, a few hidden plants had been leaving debris in the gravel so I did that clean and moved some around. I have only done 1 water change today so far there was about a gallon of evaporation and I took out 3 gal. Putting back 4 gallons.
My nitrates are still high 40-80 so I deff want to drop those down. I'll do a 50% change and not do more than that.

I have never heard of not doing anymore than 50, can you explain? Thank you!

 

[Mebbid]

The biggest reason for not doing over a 50% change imho is the difference of pH in the tap water. If you test your tap pH when it's fresh out of the faucet and then compare it to your tank's pH there should be a sizable difference and sticking with at most 50% water change limits the swing.

It will also minimize the changes in other parameters as well which could cause problems based on their levels.

Lastly, fish tend to start freaking out if their water levels drop too low stressing them out a lot.

 

[Jujubee]

Well thank you for that mini lesson. I have done bigger changes on the tank while it was cycling due to having fish in. I just did a 50%
And will do another reading I'm positive I'll have to do another 50% to bring nitrates down to a good level.

With me being gone for those 10 days since you believe my tank is going through a mini cycle what kind of rises or drops do you think I should be prepared for when I get back? I plan to get all levels down and if need be water change before I leave tomorrow. I'm a little freaked out bc I don't want to loose anyone :/ I have no one to watch my fish so they will have to nibble on the plants and find algae which they already do. But that leaves me with 10 days of no water changes.

My 10 gal is empty so I'm not worried about that. My 30 gal is doing great, I'll do a water change tomorrow and feed them before I go. The lights are on timers set for 6 hrs.

 

[Mebbid]

I'm not sure it's doing a mini cycle, rather your tank likely just got flooded with nutrients. Mini cycles sort themselves out in short order though so I wouldn't worry about it a whole lot.

 

[Jujubee]

That makes me feel a little relieved. I worked very hard getting all my tanks cycled before December knowing id be leaving. I've had some of my fish since day one when they were just in the 10 gal. Then they had babies the only new addition is my beta who I've had for several weeks now maybe a month.

I was really stressing out. Thank you for your help now I can relax a bit and cross my fingers all goes well thank you thank you!