PWCs?

[onah]

ok, over the past month i have been doing alot of PWCs, and i cant help it think this has an adverse effect on growth in my tank. Is it ok to take this much water out on a reg basis, when my tank is barely in the early stages? For that matter what about the later stages, once the tank is more established? some cleaners tell u never to take out more then 10% a wk, some say 20% every other wk, i have been told by a person to just let it sit(that it would take care of itself), and i know that cant work. Can someone(s) please explain this to me!?!?!?!?

 

[scalesojustice]

if by "early stages" you mean cycling, then you are going to be doing a lot of pwc to keep your ammonia and nitrite level down. chances are you won't see too much "growth" within a month as you are basically just trying to keep your fish less stressed and alive. while your tank is cycling, you should be taking that much water out, if it just sat there your fish would die as the ammonia and/or nitrites would build and you don't have enough bacteria to convert those two killers.

right now, you basically tend to take out as much as you need to get your nitrites and ammonia levels down, generally between 10 to 20 percent a couple times a week.

once your tank is "established" or cycled, you'll have to keep an eye on it for a while, but you'll generally fall into a pwc of 10 to 50 percent (depending on personal preference and desired water quality) once a week, as general maintenance.

don't worry, you aren't taking out too much water. if you don't have a test kit, i'd recommend it as it is a visual representation of what is invisibly going on in your tank.

 

[MSU Fan]

From my perspective:

If you are still cycling -
Fishless - there is no need to do any pwc's until the tank is cycled
with Fish - You will most likely have to do pwc's to keep you fish alive and the ammonia and nitrites at reasonable levels. the pwc level is determined by the amount of ammonia or nitrite that needs to be removed (eg, at 2ppm ammonia, a 75% pwc will reduce to .5ppm, which is considered the maximum constant level to maintain. absolutely do not gravel vac though - just pwc).

If your tank is established, doing 25-50% pwc's if not planted is fine - you could probably even go 2 weeks if your bioload is not that high. If your tank is planted and/or have a high bioload, I would recommend 50% weekly if everything else is in check (especially if fertilizing).

this is just my opinion - there are varying views on this, but the plan I just stated seems to be a pretty common routine.

 

[kostasonia]

why should someone make bigger PWC if the tank is planted?? There is something i don´t get here..

Plants somehow grow with nitrates correct?? then if the concentration of nitrates can be kept lower if you have plants, it should be that if you do NOT have plants then you have to make bigger PWC to remove nitrates?

Am I missing something??

 

[JRagg]

There are multiple schools of thought for planted tanks. Some say that you should never have to change the water, and that the only ferts necessary are foods for the fish. This is still a little controversial in the planted world.

A much easier way to raise plants involves a large weekly water change to replenish trace nutrients and sort of "reset" the tank parameters. With high light tanks you usually have to add nitrates on top of what your bioload provides anyways. And yes, a planted tank that never gets a PWC is healthier than a non-planted tank that never gets one. The nitrates are much lower, but the plant growth is not as good (and healthy) as the planted tank that gets regular water changes.

 

[coldmachineUK]

I always find if I do large pwcs (of more than 30%) then my fish begin flashing (especially my loaches). This suggests to me that they have become stressed as water params are altered on a moderate level (though not extreme).

I keep to 20% twice-weekly changes (or if I miss one, I do one 25% weekly change), using Wednesday and Saturday as my assigned days.

Everyone has a different routine, I don't think there's a 'right or wrong' way about it: you'll eventually get a feel for what works for your fish and find the right balance I'm sure