I'm trying to get opinions on what levels of nitrate I should use to trigger a WC for my patio pond. For my discus and catfish tanks its 5ppm but I'm thinking the pond might be ok at up to 30ppm which would make WC's easier and only weekly.
What are everyone elses opinions.

30ppm is ok but a sick or stressed fish may not handle this (40ppm tops for any healthy goldfish )letting it sit at 30ppm will risk it going higher at the end of the week and you will find yourself doing constant waterchanges to bring it down to 30 just to let it get to 40 in no time .running high nitrAtes will cause your fish to flip so the lower the number the better so at the end of the week you are still in a safe range and if you find on waterchange day you just don't have time letting it go an extra day is ok I think of it as breathing room

I'm finding that it sits at about 30ppm after a week and then drops to about 10ppm after a 50% WC so I'll try weekly WC's for a while and see how the figures stack up.

I don't let the nitrAte in my tank exceed 15ppm i have a fish with a very sensitive swim bladder and anything over 10ppm sets him off. 30ppm is fine although as Hi-d has said a stressed or sick fish may not be able to cope with it. 20ppm is something that is good to strive for before a water change at least in my books it is anyway. Generally 40ppm is the highest it can be before it may start to mess with the Goldfish's swim bladder and cause other problems. So in other it is the safest high range for NitrAte in a goldie tank. Although it is not advised some fish can cope at higher levels but then you need to look at the effect it will have on the fish's immune system and other contributing factors.

My nitrates are always around 5ppm, live plants helps plenty with nitrates. =)