when does a water change become irrelevant

[kien]

Originally Posted by Aquattro

I think that's a reasonable question only if we assume a close to 100% efficiency in our methods of removing and adding things. But I'm sure for every cup of crap my skimmer pulls, it leaves a cup. Carbon? Is it removing everything bad? For how long? What is dosing/balling adding that we don't account for? Is it harmful if it builds too high? In my mind, all these things simple prolong how long you can go between changes. For my comfort level, that's 2 weeks. Maybe I can go longer, maybe not. There's really no way to tell. So based on the effort it takes and the cost of salt and water, I've chosen a schedule that works for me, my wallet and my tank. As I said earlier, using the same equipment across multiple tanks, this one, with the more frequent changes, is by far my most successful tank. YMMV

I do have an ORP probe and it does fluctuate up and down. I never really payed much attention to it because it didn't move all that much. Even when I'D go a month without a water change I never noticed a significant change.

We all know that every tank is different so ya, your mileage will definitley vary. What's interesting is that there are people who do very little water change and seem to get by just fine. The water change schedule is all over the map.

I'm kinda in the same boat as you. I'm on a two week schedule that seems to work best for me (and my wallet too). I used to do weekly but can't accommodate that anymore. The tank doesn't seem to care.