Nitrate Readings

[Gone Fishing]

Hi All,
I would like to know when one should do a water change according to nitrate readings.
I was thinking when it gets to 20ppm.
Currently I have water readings of
Ammonia=0
Nitrite=0
Nitrate=15
Ph=6.5

I have;
1-12cm Discus
3-10cm "
2-9cm "

I have a pair of discus partitioned away from the others at the moment due to the fighting, they'll be be put into a breeder tank probably next week and I want to get a 10cm Blue Turquoise to replace them.

2-medium Congo
2-medium loaches
2-adult bristlenose catfish
4-small baby Bristlenose catfish

3-Logs
3-Anubias Logs

in a 200ltr, gravel filled, top filtered tank
I also have Ehem filter media and a puragen pouch with the top filter box.
All fish seem to be happy, but I want to grow them out quickly to full size.
What do you think?

Many Kindly Fishy Regards
Jason

[Merrilyn]

Jason, try to keep you nitrate levels below 10 for optimum growth. In fact a lot of breeders (and I'm one of them) aim to keep nitrates below 5.

Increasing the number and volume of your water changes is the key :P

[ILLUSN]

i like to keep mine below 10, 0-5 in my breeding and fry tanks.

mind you 15-20 is proably a better figure for a full blown planted tank.

if you want them to grow big fast, keep the nitrate low.