How to replace biomedia? (without ammonia spike)

[Sf1]

Hi,

I want to swith from Fluval C-Nodes to superior Seachem Matrix bio media.
I cannot change it in 1 shoot. So, how can I do that to prevent evil ammonia spike?

1 by day? 2-3 by week? Or how?

Thanks

 

[Fishguy1111]

I would say to do it safely: replace a third of them at a time, every 3 weeks. it'l takke a while, but its not worth the risk to rush it.

 

[Fishguy1111]

every 2 weeks would work too, now that i second-think it.

 

[Sf1]

Thanks, I think a 1/4 every 3 week will be OK.