QUOTE(dragonhart @ Thu, 06 Apr 2006 5:27 pm)
hi,
is 50% twice weekly Equivalent to 100% weekly? what are the pros and cons? thanks,
jason.
Let me try answering this tough question.
Actually subjective as it depends on your load and your filtration efficiency to maintain good water quality.
50% twice weekly:-
Pros: Good in a way that water is renewed more frequently and any of contaminants or growth inhibitor your fish may see will be diluted. Infact, I will think 20% water change daily will be even better. Your fish will certainly grow better with this methodology.
Cons: More handling and maybe more stress to you and your fish. Also risk of fatality cause by mishandling is higher.
100% weekly:-
Pros: Totally new fresh water given, risk of left over is eliminated.
Cons: Fish needs to tahan for one week before water change. If you have a loaded tank with poor filtration and heavy feeding, this may post a problem. Also, fish needs to adapte to a totally new environment upon every water change. Water handling must be with great care to ensure we get back the original condition. On top of that, 100% water change is more taxing, water must be fully drained and top-up.
My preference is more regular water change.