How do you know the "right" amount for water changing?

[trennamw]

Is more always better? And how do you know when you're changing the right amount? Presuming it's a tank that's 29 gallons or more.

Aqua Advisor tells me my tank needs a weekly water change of 15%, but I hear/read/don't disbelieve more is better.

But going overboard can stress fish too, right?

 

[Caliban07]

Is more always better? And how do you know when you're changing the right amount? Presuming it's a tank that's 29 gallons or more.



Aqua Advisor tells me my tank needs a weekly water change of 15%, but I hear/read/don't disbelieve more is better.



But going overboard can stress fish too, right?

Yes and no, good water chemistry stability is imperative to the health of the fish.

Use your nitrates as a guide. Try to ensure a nitrate reading if around 5-10ppm come your weekly water change. If your nitrates are exceeding this then you know you are either a) not changing enough water b) you are overfeeding c) you are over stocked d) not cleaning the substrate/filter media out enough. Or a combination if a through to d.

Remember the filters do not remove detritus, they collect it. Keeping it clean keeps nitrates in check and increases biological filtration efficiency.

I tend to do a thorough clean every couple of weeks including a 50% water change then a 25% in between.

 

[BBradbury]

Hello tren...

Tanks up to 30 gallons need half the water changed every week. Water changes less than that amount won't remove enough dissolved waste to keep the fish and plants healthy. Don't join the "Water Change Slackers' Club", change half every week. The tank inhabitants will reward you with long lives and beautiful color.

B

 

[Caliban07]

Hello tren...

Tanks up to 30 gallons need half the water changed every week. Water changes less than that amount won't remove enough dissolved waste to keep the fish and plants healthy. Don't join the "Water Change Slackers' Club", change half every week. The tank inhabitants will reward you with long lives and beautiful color.

B

Lol B.

I've just been reading a thread where you posted that you just top a tank off. I know this is a different case but you have a hand in both clubs

 

[PJFISH]

Hello tren...

Tanks up to 30 gallons need half the water changed every week. Water changes less than that amount won't remove enough dissolved waste to keep the fish and plants healthy. Don't join the "Water Change Slackers' Club", change half every week. The tank inhabitants will reward you with long lives and beautiful color.

B

+1 totally agree! 50% a week

 

[BBradbury]

Hello again tren...

Yes, that was a totally different type of tank. I used Chinese Evergreens emersed to maintain pure water conditions. A tank of this type needs no mechanical filtration and no water changes. You do need to top them off to replace water lost to evaporation. Hopefully, no one was confused. I do have the standard tanks that require large, frequent water changes.

B

 

[azmodan]

Is more always better? And how do you know when you're changing the right amount? Presuming it's a tank that's 29 gallons or more.



Aqua Advisor tells me my tank needs a weekly water change of 15%, but I hear/read/don't disbelieve more is better.



But going overboard can stress fish too, right?

It'll depend on your stock, filtration, if you have live plants, etc. Essentially your water testing will determine the eventual percentage you'll settle on, but even that may change if your stock changes, plants are added, and so forth.

 

[trennamw]

Lol B.

I've just been reading a thread where you posted that you just top a tank off. I know this is a different case but you have a hand in both clubs

I must have been unclear in that other thread, I pretty much never top a tank off. My betta tank evaporates more and I add distilled water if I add anything. It gets a 50% water change every week with a few smaller changes in between and I test it every few days. I don't top off the 29, it never needs it.

Maybe you read how I do a simple, passive water change occasionally with a slow drip from aquarium tubing. That's not my weekly big maintenance routine, it's something I do a few times a week for more changes. And yes I understand five changes of 10% isn't the same as one 50%.

My 29 gallon has been at about 2-3 ppm nitrates and dropping, and I do have live plants.

I'm just curious what people use as their hard and fast indicator ... A schedule or water tests.

Yesterday I took samples to LFS, one tap and one "dirty" tank water (due for a water change). He tested the dirty tank water then said "ok now let's tests the dirty water". I explained my approach to water quality and got a lot of compliments.

If I go by my nitrates, aqua advisors suggestion is working. If I were to do 50% a week I'd have no nitrates.

I'm not trying to be lazy I'm trying to understand what's best for my animals. My tap water is practically distilled, I'm using coral for buffering capacity because I get wild swings with other buffers, and 50% a week creates greater fluctuations in KH and pH. If my fish really need that much of a water change, it's iust as much trouble as a 20%. I'm just balancing all the variables. Given what I add to the water for GH and KH, consistency with TDS is important.

I also asked to get a general range of opinions that's useful for lots of people. 50% a week is a great rule but too little for some people and too much for others. Nitrates at 5-10, and good stable number on all other parameters, is a little less one size fits all.

 

[BillD]

I don't think 50% is ever too much. Just because nitrates are low or even gone, doesn't mean that other metabolic wastes aren't building up in the water.

 

[trennamw]

I don't think 50% is ever too much. Just because nitrates are low or even gone, doesn't mean that other metabolic wastes aren't building up in the water.

That's the kind of feedback I was looking for. What other wastes do you mean?

 

[Fresh2o]

Nitrogen, phosphorus, potassium, calcium, magnesium, inorganic and organic carbon plus a variety of trace elements. Yes this sounds like plant fertilizer.
http://www.google.com/url?sa=t&sour...hIGgBw&usg=AFQjCNGhweCAzhJdNgd2H00mgqbs4pgo2Q

 

[phishiephishie]

I've never had any issues when doing large water changes once per week. I've found that both fish and plants love them

 

[trennamw]

Is there a way to know you're changing enough, other than everyone seems happy and healthy? Does a tds meter pick up on those or just on minerals?

And while the nitrate test doesn't measure those other wastes, wouldn't the correspond in a fairly consistent ratio? We don't have fish that poop without putting out ammonia, do we?

I was doing 50% every day with the betta and kept fighting fin rot. Cutting back a little bit this balanced point where he got a lot more active and started building bubble nests.

It still seems like there may be different answers for different tanks and types of tapwater.

I'm ordering a tds meter just because I'm adding so much to the water for GH and KH. It's clear sometimes even when I make the GH and KH (and pH and temp) match pre and post water change, there's something that is different enough that I get swings in how content the fish are. It's most pronounced in the betta tank of course. Sometimes a water change is followed by a lot of moping until I change it again.

 

[Mebbid]

Generally, unless there are extenuating circumstances like the source water being problematic for the health of fish; more is better. 50% weekly is a great schedule to have and in almost all cases is plenty. Other than that, the only real indicator of the need for a water change is nitrate level. Tds isn't really an accurate measure, as well as most other things in your tank.

 

[Delapool]

It's quite strange sometimes. I have a platy in a 5 gal tank and did a 80% pwc on weekend. Fine, no worries.

The same platy used to sulk on a 30% pwc in the much larger DT. Same water used. Quite confusing.