Tank cycled, need help!

[LemmiWinks]

7 weeks later my 29 gallon tank is cycled..now what!? Do i do a giant water change? Also while staring at my empty tank over those 7 weeks i realized i want a more natural look and would like to swap out my gravel, will this kill my cycle? i was thinking about taking most of the gravel out and maybe putting it in a giant bag with holes and let it sit on the new gravel, will this work or will it hurt my cycle?

 

[LemmiWinks]

anyone?????????

 

[jcolon]

7 weeks later my 29 gallon tank is cycled..now what!? Do i do a giant water change? Also while staring at my empty tank over those 7 weeks i realized i want a more natural look and would like to swap out my gravel, will this kill my cycle? i was thinking about taking most of the gravel out and maybe putting it in a giant bag with holes and let it sit on the new gravel, will this work or will it hurt my cycle?

Once your tank is cycled, a weekly 25% PWC's pretty much all you need. Large water changes should only be if you find ammo / nitrites or large nitrates.

As for switching the gravel ... doing it in one shot could lead to a mini-cycle since a good number of BB live in the substrate. However an empty tank is also the best time to do it since no fish would be harmed by a mini-cycle / ammo spike. I'd say go for it ... but be prepared for more testing and PWC's.
You could do it in 1/3 ... change 1/3 now ... wait a week for the BB to establish, do another 1/3 ect. What are you looking to change the substrate to? A different type of gravel? sand? ... just curious.

 

[eco23]

The key at the end of your cycle is to do a big enough pwc to get nitrAtes below 20. If you've got the heater cranked up for the cycle, remember to turn it down.

Switching substrates is likely to cause a mini-cycle, but as long as you keep a sharp eye on your levels and are prepared to do pwc's as necessary...it won't be the end of the world. Right after your cycle ends is a delicate balance point, so it's not the best time to make changes...but if you have the option of switching the gravel, then testing your BB with the lure ammo a few times you should be good to go. Leaving some of the gravel in the yank will be a help, but I wouldn't believe having it in a bag with holes is going to be as efficient as it was.

Did you cycle at 4ppm? If so, losing the BB in the substrate shouldn't have a major impact on your ability to keep the tank stable. 4ppm is designed to be overkill and grow enough nitrifying bacteria to handle a huge bio-load all at first.

Personally I'd hold off on fish for a few more days, switch the substrate, continue to dose the ammonia to ~3ppm and make sure it can be dropped within 24 hours.

Check out the guide and FAQ in my signature for a bit more info

*Same time, good answer Jose