How often should I change my water? What %?

[DragonFish71]

I understood the post to say that they'll have those fish (as in, they dont have them yet)... unless I read it wrong


As for the percentage, it really all depends on your tests... Personally, I do 50% weekly in all of my tanks. Just gives me peace of mind. Most people are fine doing 20% weekly. If your ammonia and nitrite stay at 0 and your nitrate stays below 20ppm with 20% pwc's, thats good enough... I'd recommend 50% just because its easier to judge, and clean water is always a good thing

He has 1 betta in there already if I read his other posts correctly

 

[DragonFish71]

Wouldn't 2 bettAs fite?

He's making a divided tank.

 

[HN1]

Not worth replying to.....some people have no idea what they're talking about.

Spiffy attitude there and you're the one that's wrong to boot.

I agree with the others that 50%+ weekly isn't bad at all. Think about the turnover of the rivers, lakes, etc that most of our fish originally come from. Those water bodies have ZERO.something ppm of nitrate usually and a higher DO than we typically maintain in our tanks. If you're doing smaller changes, you'll also be fine. For awhile. The buildup of pollutants will gradually increase and you'll end up with stunted fish and OTS. I'm looking for a graphic that someone produced here locally depicting the differences between weekly 50% and daily 10% PWCs. I'll post that as a reference for everyone but you. It seems there's nothing you don't already know judging by your posts so far.

Edit: Found one of the threads that I was looking for. http://www.atlantaaquarium.com/forum/viewtopic.php?id=2146&p=1. I've seen one including biweekly, but can't find it yet.

 

[logansmomma1228]

HN1, what does OTS and DO mean in your previous post?

 

[mfdrookie516]

OTS= Old Tank Syndrome
DO= Dissolved Organics (sometimes called DOC's or Dissolved Organic Compounds)

 

[logansmomma1228]

thank you the abbreviation thing doesn't always work, when you hold the mouse over them

 

[HN1]

OTS= Old Tank Syndrome
DO= Dissolved Organics (sometimes called DOC's or Dissolved Organic Compounds)

Actually, it was meant as Disolved Oxygen.

 

[mfdrookie516]

oh... well... hmmm... but it is true about DOC's right? wow, I feel kinda stupid now lol

 

[logansmomma1228]

Lol I shouldn't even say this but here goes: aren't they essentialy the same idea? I amsure it's 2 totally different things, but they both lead to waste correct? I feel stupid not knowing how oxygen can dissolve lol. Can't wait to get my butt back in school

 

[HN1]

Not stupid at all. There are way too many TLAs used in daily life now for anyone to remember them all.

Disolved O2 is very different than DOCs and important especially as temps go up. The ability (as I know you know) for water to hold O2 is inversely proportional to the temp. As temp goes up so does fish metabolism and the rate that they use O2. So increased temp is a double whammy, less DO and more demand for it. That's why aeration on tanks being treated with heat for ich can make a big difference.

The primary test used to evaluate the health of a stream in the adopt a stream program is DO and there is a direct and unavoidable link between the DO level and the sensitivity and diversity of macro life found. I've found it kinda odd that we don't discuss it more related to aquaria.


TLA= Three Letter Acropnym.

 

[mattrox]

I have been known to do upto 70% pwcs at times instead of 40-50%. It is usually when I get in to do a big gravel vac. The fish respond well and are very active afterwards. I only do big pwc's in summer when the tap water is not cold.

I believe that a big pwc will kill the fish only when there hasn't been a pwc in months. The nitrogen cycle produces H+ ions (acid) when ammonia is converted to nitrate. So after a long time the water chemistry can gradually change if the water is buffered (in soft water the pH crashes and fish can be killed quickly). The acid will remove carbonate, and the complex water chemistry will be altered over time. A big pwc will mean a big change in the other parameters, even if the pH of the new water is quite close to the tank water pH. Buffering only keeps pH stable not other dissolved ion concentrations.

 

[meegosh]

Edit: Found one of the threads that I was looking for. Atlanta Area Aquarium Association Forum / Water Change 150 gal. I've seen one including biweekly, but can't find it yet.

Thanks for posting that HN1, very interesting read.

 

[corrado33]

Jeeze those graphs are amazing...

So in summary... You can do a weekly water change of amount X, or you can do a every other day water change of amount X/3.5 to get roughly the same results. Example, you could do a weekly 35% water change, or a water change every other day of 10% to get the same results.

(Although with weekly water changes, the AVERAGE waste concentration is slightly lower, however you have bigger swings in your water parameters)

I personally do a 40%-50% water change every week because that's how much water it takes me to clean the gravel in my tank. Although now that I have plants that might change a bit.