Water changes

[Phaedrus2129]

Instead of doing one big weekly water change, might it be better to do a smaller water change daily? For instance, rather than doing a 20ga water change on the weekend, what if I did a 5ga water change every day? I'd be changing out 35ga a week instead of 20ga, taking just 10 minutes a day, rather than having to make time for a 30-45 minute big change, plus less stress on the fish. This would also help reduce the impact of the nitrites in my tap water, as they'd be added in tiny doses rather than one big .25ppm/20ga injection.

Does this sound like a good idea, or are there problems with this?

[Lady Hobbs]

No. Tiny water changes do nothing much so you'd be doing numerous changes during the week that are not helping.

[MChambers]

I actually think it would be ideal, because it would, as you say, have less chance of shocking the fish, and, at the end of the week, you would have replaced as much or more water.

The challenge is finding the time to do all the changes.

[Reefkeeper18]

I don't really think that those smaller water changes are better because your just making yourself do the same amount of work just over a longer period of time and they are not proven to be effecient

[KingFisher]

I actually think it would be ideal, because it would, as you say, have less chance of shocking the fish, and, at the end of the week, you would have replaced as much or more water.

The challenge is finding the time to do all the changes.

No, it would definitely not be ideal. The percentage of waste that gets removed with such a small waterchange is too small to keep up with the production of waste.

As far as the stress on fish goes, the stress cused by living in water that contains high levels of waste greatly exceeds the stress caused by a large weekly waterchange. Healthy fish kept in clean water will be much better able to handle stress than fish weakened by poor water quality.


I saw a chart which showed how long it takes for waste to build up in a fish tank over time with varying percentages of water changed. I will try to find it again and post it here.

Edit: Found the chart, it is from MOA's site. Here is the link: http://sites.google.com/site/moashow...nges-necessary

[rich311k]

Let us assume we have 100ppm something and we add 10ppm of it every day.

if you have a 100 and take out 50% you have 50
buy the next water change you have 50 + 70 = 120

next week another 50 = 60
week 3 60 + 70 = 130 after change 65

if you take out 100 and take out 15 you have 85
add 10 then take another 15 = 80.75
add 10 then take another 15 = 77.13
add 10 then take another 15 = 74.06
add 10 then take another 15 = 71.45
add 10 then take another 15 = 69.23
add 10 then take another 15 = 67.34

next week
add 10 then take another 15 = 65.79
add 10 then take another 15 = 64.42
add 10 then take another 15 = 63.25
add 10 then take another 15 = 62.26
add 10 then take another 15 = 61.42
add 10 then take another 15 = 60.70
add 10 then take another 15 = 60.09

You get the idea, it comes out close to the same.

[Spardas]

Changing water doesn't stress the fish as much so long as the incoming water matches with the water in the tank. I do over 80% water changes twice daily and my fishes welcome it.

Good link, KF. I'm going to look at the math.

[AndorranPrince]

He's doing small water changes more often. The percentage of water changed is MORE than otherwise, it's just less strain. Kind of like how discus keepers do 20% thrice weekly instead of 60% a week. It's less stressful, especially if he's got nitrites in his tap water.

[Phaedrus2129]

Edit: Found the chart, it is from MOA's site. Here is the link: http://sites.google.com/site/moashow...nges-necessary

There's another chart on there, this one:



That would seem to suggest that it's optimal to do a 10% (5ga) change every three days, or a 25% (11.5ga) change every 7 days, otherwise the RWI gets too low. For 20ga (~40% changes) it seems it would be best to do it every 10-14 days.

[BiGBlak]

When it all adds up it the same . If you have to do a 50% water change a week based on you load you could easily split that up in two 25 percent water chNges . Thts what I do and never had a problem so why cNt you do 10% every day for 5 days the water is still getting changed. But I would only do that on large tanks 55 plus it seems since your talking about 20% so do you have a 20-29gL ? 50% on that is a quick water change even a 75-80% is so you shouldn't even consider the 10% method IMO