Water changes

[Aquattro]

Marie, I completely agree. While I regularly do 10 or 15% changes for maintenance, if I thought I had an issue that a 100% change would fix, I'd do it ( well, back when I had a 100g tub for mixing). The "rule" of 10% is just being safe and we always tout "make small changes slowly" in a reef, but properly prepared water is just like the water in the tank without all the crud in it.

[tang daddy]

A 100% W/C is like starting up a new tank and putting a whole bunch of corals in. Hey that's basically what I did well not that fast I waited every other day.

[StirCrazy]

I usaly only did 20% but I moved my tank and/or redid stuff and 5 times I did 100% waterchanges. never lost anything on a 100% change or suffered any ill effects. just match salinity, PH and temp as close as you can, and away you go.

Steve

[marie]

It's hard to get a debate going when everyone agrees with you

Originally Posted by StirCrazy

I usaly only did 20% but I moved my tank and/or redid stuff and 5 times I did 100% waterchanges. never lost anything on a 100% change or suffered any ill effects. just match salinity, PH and temp as close as you can, and away you go.

Steve

It's not very cost effective to do large water changes all the time, only when you have problems . In fact I'm reaching the point where I don't do water changes unless I notice problems starting

[PoonTang]

I think it would depend on what the problem with the old water is. The key is stability. If it just a routine water change where the new water was basically the same as the old water than a 90% WC shouldnt be harmful. If it is an emergency WC than a 50% change could be fatal. Eg. what happens if your tank has a problem and get a pH spike of 9.0 and so you do an emergency WC and thus cause it to drop to 8.2 in a matter of minutes? Wont be a pretty site afterwards. The cure may be more harmful than the disease?
I think you need to know exactly what the condition of the old water is before we make large WC. Would kind of be like adding new corals and fish to our tanks with no acclimation what soever

[marie]

Originally Posted by PoonTang

I think it would depend on what the problem with the old water is. The key is stability. If it just a routine water change where the new water was basically the same as the old water than a 90% WC shouldnt be harmful. If it is an emergency WC than a 50% change could be fatal. Eg. what happens if your tank has a problem and get a pH spike of 9.0 and so you do an emergency WC and thus cause it to drop to 8.2 in a matter of minutes? Wont be a pretty site afterwards. The cure may be more harmful than the disease?
I think you need to know exactly what the condition of the old water is before we make large WC. Would kind of be like adding new corals and fish to our tanks with no acclimation what soever

Well I've been thinking about that theory, that corals get used to bad water conditions and giving them clean water conditions will make them react negatively but I just don't think thats true.

If you live in a smoky house and end up with emphysema and then move out into the fresh air, it's not the fresh air that kills you, Your just too late in moving out of the house. And i think it's the same with corals, sometimes they are just too far gone for a complete water change to save.

Oh and I have raised my tank ph from 8.0 to 9 in a very short time (adding kalk too quickly in a tank with no sump ), it wasn't a problem

[marie]

Corals are actually hardy creatures that can take all kinds of abuse temporarily (inluding sitting in a stainless steel sink for 3 hours and then having a cold coffee bath, can anyone say acidic ) but the key word is temporary.
It's making them live under foul conditions for a long time that does them in. They are wild animals and like all wild animals they can't afford to "look sick" or they will be eaten so they "look" healthy until they are just about dead