Water Changes

I was looking at a fabulous discus tank yesterday on you tube, the guy said if you want "any" fish to do well, smaller WC more often are the key to really healthy fish, rather than one large one, I am doing a 30% WC every Friday, I would appreciate your thoughts on this.......

Too late for a long answer.....

the short answer....

In a typical community aquarium, provided that the tank is not overstocked, you don't over feed, and that when you do the water changes you use a gravel cleaner to syphon debris out of the gravel, 10-20% weekly is all that's necessary.

For more heavily stocked tanks, especially if they're heavily fed, for example, a grow on tank for babies, then a 10-20% water change every few days is usually adaquate.

Some people do advocate larger changes, I think a lot depends on the quality of the water you put back, personally I'm not a big fan of declorinators & favour leaving the water to stand for a few days, with aeration, but the larger the water change, the greater the risk that you will upset the filter bacteria, or cause a serious swing in water chemistry, or upset the fish with chlorine, or the dechlorinator of your choice!

the Key is to monitor your water quality, provided the nitrates are below an acceptable level, personally I work to 50 - 100ppm, many would advocate lower levels. And your KH above 2DH and reasonably stable, then you're doing sufficient water changes. If you're not doing sufficiently frequent/large water changes the nitrates will gradually creep up, and your KH is liable to gradually fall, if the KH drops below 1 DH then there is a serious risk that your pH might crash.

Thanks Rob, a pretty good short answer, just what I wanted to know...........