Filtration and water changes

[B-O-F]

I have read somewhere on simply that if you do 50% water change a day then the water will never contain more than one days volume of ammonia etc. ( which makes perfect sense )

How much is to much will obviously depend on how many fish you have in the tank but at what stage could water changes replace the need for ANY filtration ? If you were running a constant flow system equalling say 100% per day would biological filtration still be needed ?

[OriTeper]

this is from another thread (Hans answer as to how i should plan my 250gal) :
http://forum.simplydiscus.com/showthread.php?t=60275&page=2



It is simple- do 125 gal water change every other day and filtration system should be not important- even NO FILTRATION will be good enough. But remember- water for WC must be aged ;).
Hans

[B-O-F]

:)
I thought I had read through all the posts in the last couple of weeks. Must have missed that one.

125 gal wc every other day would only equate to 25% per day. Many people hear advocate 50% per day and yet they still use filters..... Why ?

[OriTeper]

some reasons i can think of:
- in case you cant do water changes for a few days (going on vacation etc.) i assume you would want an established filter running.

- keeping the water clearer

- adding chem filters (peat, carbon...)

- water circulation for balanced temperature throughout the tank (if your going to have a pump running , might as well make it filter the water at the same time)

- sleep better at nights (not having to worry about if its ok to not having a filter :D )

[kaceyo]

I'm not sure, but believe Hans was talking about planted tanks. I've heard of people doing multiple (at least 2) 100% wc's daily without using filters. It is of course partly dependant on the stocking level, amount and type of foods, pH etc whether more or less wc's would work. If the pH could be kept low enough the ammonia could climb pretty high without causing problems.

Kacey