# [Wet Thumb Forum]-Weekly Water Changes



## Dave Cushing (Aug 4, 2003)

I am developing the maintenance routine for my new tank and I see conflicting advice on weekly water changes. 

I have seen people recommend any where from 10% to 90% a week.

I know that I will get a wide range of answers, but what do most people think is about right for weekly maintenance.

Dave


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## Dave Cushing (Aug 4, 2003)

I am developing the maintenance routine for my new tank and I see conflicting advice on weekly water changes. 

I have seen people recommend any where from 10% to 90% a week.

I know that I will get a wide range of answers, but what do most people think is about right for weekly maintenance.

Dave


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## ekim (Jan 31, 2004)

Here is my opinion on it,

Low light/nutrient tanks 25% bi-weekly
High light/nutrient tanks 50% weekly
Grow out tanks for juvenile fish 50% daily

That just my opinion!









*My Digital Gallery*


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## Vicki (Jan 31, 2003)

Mike and I are pretty close on this one.

High light, high nutrient tanks: minimum 50% weekly. If I have time, I like to do 50% twice a week, because I don't need to add additional phosphate that way.

Low-moderate tanks: I generally do about 40% weekly.

Fry and breeding tanks, q-tank (when occupied): 40-50% daily.

http://www.wheelpost.com


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## Roger Miller (Jun 19, 2004)

I change 15% per week in all my tanks.

I hate to fly in the face of popular wisdom (no I don't), but I don't see much good reason for doing 50% weekly water changes in a planted community tank.


Roger Miller


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## Vicki (Jan 31, 2003)

Many people don't. I've just always done it for my fish's sake, and when I started seriously growing plants years ago I kept doing it, I didn't see any reason not to. I've kept doing it since then because my tanks are crystal clear, my fish happy, healthy and long-lived and my plants do well--and I have little or no algae. But there are many ways to success in this hobby, and nothing is black and white except my golden rule--if it ain't broke, don't fix it.

http://www.wheelpost.com


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## Kevin Jones (Apr 4, 2004)

I generally do a 30% 2 times weekly to all my tanks... more if I've been mucking around in one and the water seems cloudy


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## perrush (Feb 24, 2003)

30% a week here.

For two reasons :
to 'reset' the nutrient levels so no build up of nitrients arise
and 
to fertilize traces (my tap contains 0.005 ppm Cu, 6 ppm K, ...)

I think too little can be more harmfull than too much

--
English isn't my native language, but I guess you already noticed that ))
--

Perrush


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## ScottH. (May 13, 2004)

I do exactly as Roger does. 15 percent weekly. Sometime I do more just for the heck of it. I would say that newer fresher water is always good. Most of my fish come from streams where they constamtly have new freshwater. So I think they should have it the same in the aqarium.

My goal is a sea of green.


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## Dave Cushing (Aug 4, 2003)

Seven posts and five different answers. I knew this wouldn't be a simple answer though. I think I will start off with 20% weekly. That is a good round number on my 50 gal. 

Thanks for the input.

Dave


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## Vicki (Jan 31, 2003)

You know, Dave, the common thread is that while we may differ as to how much we change, we ALL do water changes weekly. I think having a regular weekly maintenance routine is what's important; how much water you change is largely a matter of personal opinion and inclination (although the characteristics of the tank, your feeding habits, bioload, etc., are all important factors, too). Doing ANY amount is better than being lax or inconsistent about your maintenance regimen.

http://www.wheelpost.com


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## Robert Hudson (Feb 5, 2004)

I do small water changes every two weeks, sometimes every three weeks. If I was keeping Apistogrammas or some other sensitive soft water fish, I would do it weekly. If you do to large a water change too often, I think you can actually do more damage than good to C02 and nutrient levels.

Robert
King admin
www.aquabotanic.com


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## perrush (Feb 24, 2003)

> quote:
> 
> Originally posted by Robert H:
> If you do to large a water change too often, I think you can actually do more damage than good to C02 and nutrient levels.


This I don't understand.

CO2 is taken up directly to the levels it was before the waterchange (pH controlled), so no problem there

nutrientlevels are just 'set correct' each time you do a waterchange. when you dose fertilizer without waterchanges, you never know if the fertilizer is taken up or not.

--
English isn't my native language, but I guess you already noticed that ))
--

Perrush


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## Phil Edwards (Jan 22, 2004)

I tend to do 30-50% weekly in my PMDD/High Tech tanks because it's easy to remember. I've started doing 30% 2x/week on my 90g to get the crypts used to what it's going to be like with the discus in there.

In my Seachem/Kent dosing tanks I don't often do W/C. Topping off seems to work best. A 25% monthly W/C is enough for them.


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## Crocodylus (Jul 2, 2003)

I do a regular 20%-25% water change (with gravel vacuming)every week, along with cleaning out the filter


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## Tenor1 (Mar 3, 2003)

I do 30% changes 2x per week, not for the plants as much as the fishes sake. IMO and experience the fish do better with more frequent water changes. 

Regards,
Carlos

==============================
I try to keep the tank plain and simple but it never stays that way!


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## perrush (Feb 24, 2003)

why do I find WC so important when adding fertilisers.

We can't measure most of the ions correctly. But if we now the composition of are fertiliser(s) and or tapwater we might have a pretty nice idea how much of each element in the water *right after* a WC.
If we only do minot WC and we fertilize as much as we think we need to, after a few months we've no idea at all what the levels of the nutrients are (especially the micro's)

The reason for this is that we don't know for sure how much of the nutrients are taken up by the plants. So if not all nutrients are taken up and we add new ones, we've got a build up.

For NO3 and PO4 this won't happen because we can measure them. But what about K ? or Mn ??

That's were large WC come in.

Let's give me an example.

we want 10 - 20 ppm K. I know my tap has an average of 6 ppm K (got it from the watercompany). So I decide to add 20 ppm to the water with which I do the WC (some KNO3, the rest K2SO4). That water has an [K] of 25 ppm.

I do a 30% WC a week. Now 2 situation can occur :
1°) my plants consumed every K during the past week and thus my [K] level is 0. When adding 30% water with [K]=25 ppm I have at least a 25/3 = 8.3ppm [K] to start the week with.

2°) I had problems in my tank and no K is comsumed for even a long time. so my [K] will be around 25 ppm (doing those WC with 25 ppm K already for a long time), but even adding new K won't raise my [K] but I take away just as much as I put in.

so with a 30% WC I have ALWAYS a maximum [K] between 8 and 25 ppm, even without measuring. If I increase the WC to 50% a week, I have a max conc. between 12.5 and 25 ppm K.
So no chance of overdosing.

If the plants would pearl less at the end of the week it means that all or one nutrient(s) is used up, two things could be done. A larger WC (although 50% is an max) or more frequent WC's.

I find this a nice way to make sure I'm not overdosing and in the meanwhile I know my plants do get at least a minimum of nutrients

--
English isn't my native language, but I guess you already noticed that ))
--

Perrush


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## Punchy (Apr 29, 2003)

I do 30% weekly as well.


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## imported_trilinearmipmap (Feb 11, 2003)

Well I would put it to you this way.

If you lived in a swimming pool and you were never allowed to leave the swimming pool even to go the the bathroom, would you rather that I change 50% of the water weekly or 20% of the water weekly.

50% weekly water changes for all my tanks except when I slack off.

Canadian Aquatic Plant Trading Website


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## Bill D (Feb 7, 2003)

> quote:
> 
> If you lived in a swimming pool and you were never allowed to leave the swimming pool even to go the the bathroom, would you rather that I change 50% of the water weekly or 20% of the water weekly.


Well, that settles that argument! Nothing like an apt analogy!

Bill


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## Antonio Trías (Feb 4, 2004)

I make a WC about 5% every 4-5 days. I,m fertilizing with K and only correcting P and N if is needed. As a micros I only fertilize with Fe (dayly), beeing enough for my tanks the food fish an these WC to replenish the rest of micronutrients. Without adding heavy metals, I do not need reset my tank.-

Nobody better than your tank will give you the correct routine: just looking for healthy plant grow.-


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## Tenor1 (Mar 3, 2003)

Tri, there is a TV commercial playing here in Los Angeles with a little boy in a swimming pool and he says to his father "daddy, I don't have to go the bathroom anymore." IMO, you just can't change water too much, lol. I notice better fish health, grown and activity with 30% 2x a week.

Regards,
Carlos

==============================
I try to keep the tank plain and simple but it never stays that way!


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