Will adding a ton of substrate choke off cycle?

[Doc7]

How important is my sand substrate to cycle vs my Eheim 2213 for a 20 G high? I am adding plants to my tropical community 20 G high tank, and in the process, yesterday measured my sand depth and found it to be less than 1” instead of the recommended 3-4” (going with the lower end of that – 4” is a quarter of my tank’s height!)


I have been washing buckets of sand for use and am almost ready to add. My plan was to remove fish and plants, lower water about halfway, and add in the new sand on top of the old – mixing it all together is less than preferable, as there are old fertilizer tablets in there as well…


Will this choke off a significant amount of my bacteria population and kill my cycle, and my fish?


Thank you,


Doc7

 

[Doc7]

with the safety of my fish and the future impact on having a "nice" planted aquarium, i've decided to get an additional 20 g high tank to store them "bare bottom" while i do a substrate changeout complete with plant-friendlier mix layered with sand. this will be a fun project to do over the next couple of weeks/months and when it's over i'll have a spare tank that i can turn into a shell-dweller or something.

 

[Gerryd]

Hi,

Based on your fish load and available bio bed, if doing say daily 50% water changes for 7-10 days after the addition may be sufficient to keep the fish in the tank. Remember that they will need to feed the new bio bed material....

You can add a sponge or two now (float it) and increase feeding to seed it PRIOR to the addition,.

Or you can do in two stages. Half the tank, wait 2 weeks and repeat...

 

[nipat]

I've done that a few times. High fish load. Changed water on the third day, then
back to normal schedule. Never lost a critter. I've found plants helped control
the NH3/4 very well. Coupled with a cycled filter, I would not worry.