Opinions on water changes

[shawmutt]

I currently do a 20% water change every other week. I'm really nervous about changing any of my routines, I've had catastrophic results every time I do. However, I have noticed the nitrate levels have been slowly rising over the weeks. In addition, I plan on adding 4 more cardinals this weekend (I currently have 9 cardinals and 4 ottos). Do I need to do bigger water changes? Can I do 20% weekly without adversely affecting the biological filter? Are my plants going to suffer if I vacuum the gravel once a week (from taking nutrients out of the gravel)?

 

[fishfreek]

what are your nitrate levels at currently?

 

[Bearfan]

I do a 20% every week and vacuum half of the tank alternating sides every week. My plants seem not too mind. No problems with my bio filter.

How long has your tank been set up?

 

[shawmutt]

It seems to be deep orange red on the card, indicating around 40-80 ppm.