Large water changes input

[ocean diver]

How often do you clean your canister filter?

[sirruckus]

actually I haven't cleaned the canister filter - all sponge material etc. has been removed, only the ceramic balls are inside.

[sumpfinfishe]

IMO i would do five 20% changes every other day that would give your
setup a good flushing

[kien]

if done carefully (similar parameters as Aquattro suggested) a larger water change (50-80%) should go just fine. This is how I have done tank transfers in the past. Fill new tank 20% with old tank water then the rest with new water. As others have said, you don't want to be doing this on a frequent basis, but for a one or two off event for quick and short term correction purposes larger water changes are fine. A few weeks ago I did two consecutive 50% water changes in my tank to help flush out a treatment that I did on my tank.

[sirruckus]

I appreciate your guy's input on this topic - lots already!

I understand the worry people have with such a large water change, and I agree it should be avoided as best as possible. I can't say that I've done one, and most people probably cant (even those who advocate not to do one) - because it gets into an uncomfortable zone.

But one analogy I heard from someone that was successful:

consider yourself as the fish - trapped in a garage with a car running, filling up with exhaust (Phosphate levels) - opening up the garage door to let everyone out as fast as possible may shock you, but is going clean the air and.

simply - each has its benefit and each has its downfall.

[waynemah]

Originally Posted by sirruckus

actually I haven't cleaned the canister filter - all sponge material etc. has been removed, only the ceramic balls are inside.

The Ceramic balls might be the cause of your nitrates... If you have room in your sump, you might want to consider sourcing a zeovit reactor, use the zeo media and go on the base system (Start, Bak, Food). It's a fairly proven system and well supported.

[Aquattro]

Not sure what the concern is on water changes. Where does this common 20% come from? Not sure how too much clean water is going to hurt your fish, given that the important parameters match.

[waynemah]

Originally Posted by Aquattro

Not sure what the concern is on water changes. Where does this common 20% come from? Not sure how too much clean water is going to hurt your fish, given that the important parameters match.

I threw 20% out there because It's what I've had experience with. Personally if it came down to it and fish were dying, I'd do as large of a water change as fast as possible. But I don't want to be responsible for crashing someones tank with inexperienced recommendations.

[Aquattro]

Originally Posted by waynemah

But I don't want to be responsible for crashing someones tank with inexperienced recommendations.

fair enough

Think of it like this..if you bought a fish or coral, and the water was pretty close to your tank, would you acclimate or just add to the tank? Personally, if I get a fish from a friend's tank and we're anywhere near close to temp (that's all I'd look at), I dump the fish in my tank. That effectively is a 100% water change for that fish. I've never lost one to new water. Same with corals. I float a bit to equalize temp, then in it goes. Completely different water than it came from = 100% water change.
The bacteria you want to filter your tank resides on the substrate. The amount free floating will have no impact, so that's not an issue.

I suppose one caveat might be that if your tank is so filthy and the fish have become accustomed to living in sewage, too much of a good thing might kill it. I doubt this is the case

[Proteus]

I do 50% WC all the time. Though not cost effective I enjoy doing it for fun. Ans as for coral above water I wouldn't worry. Most of mine are exposed and if I'm making frags they sit on table for 5 minutes