How often do I need to change a Freshwater tank after a successful cycle

[tmhoskins]

I have seen posts on here advocating for a 50% change every week of tank water once it's established. I have been reading many other posts on different forums and that amount seems extremely high compared to other suggestions. So what is the actual amount you should be replacing each week? I have seen testing for nitrates as the deciding factor, or only a 10-15% change a week. So much info and it's all contradictory. I have even seen 50% once a month. I don't know where to begin. I am currently doing an IN-FISH cycle and I am on day 5. I don't want to kill these fish and it seems the best way to do that is to change 50% of the water twice a week as suggested on here. We have a bio-filter, air bubbler, and a heater for the fish, as well as adequate lighting.

Please HELP!

 

[charliebankston]

After cycling, depending on your bio/ fish load, you could do 25% weekly or monthly. I have some big tanks with only 1 fish, I do about a third monthly. Others, more heavily populated I do 25% weekly. I wouldn't suggest doing less than 25% at a time irregardless of the interval

 

[charliebankston]

Watch your nitrates after it's cycled and keep them under 40 ppm. And the detritus in the tank. That'll govern how often and how much is necessary. The other numbers you mentioned are just basic guidelines. Every set up is different. Like I said, at least 25% on every change tho

 

[Ktownmatt]

Like the others have said, it depends on your tank setup and when the Nitrates get close to 40ppm.
I have a planted and heavily-stocked 37 Gallon tank, and it needs a 30% water change ever 4 weeks.
I have a lightly-planted, lightly-stocked 9 Gallon tank that needs a 30% change weekly.

I like to keep it at around a 1/3 change, just so there's not as much difference (temperature and chemical) each time.

 

[Caliban07]

I have seen posts on here advocating for a 50% change every week of tank water once it's established. I have been reading many other posts on different forums and that amount seems extremely high compared to other suggestions. So what is the actual amount you should be replacing each week? I have seen testing for nitrates as the deciding factor, or only a 10-15% change a week. So much info and it's all contradictory. I have even seen 50% once a month. I don't know where to begin. I am currently doing an IN-FISH cycle and I am on day 5. I don't want to kill these fish and it seems the best way to do that is to change 50% of the water twice a week as suggested on here. We have a bio-filter, air bubbler, and a heater for the fish, as well as adequate lighting.



Please HELP!

Plants like to take up ammonia. Floating plants grow fast because they are exposed to atmospheric levels of carbon dioxide and are closer to the light, therefore they will extract ammonia from the tank for growth.

This will reduce the amount of water to be changed.

 

[fishwonder]

You should change water based on what your Nitrate level is. Keeping it under 80 ppm is the target. I do 50% water changes every 4-5 weeks. Been doing that for over 10 years now. Some info here for you.

https://aquariumscience.org/index.php/5-7-1-water-changes-in-depth/

 

[Mr. Overfilter]

How you change water, depending on your configuration, is important as well. We have a 125g long (about 72in wide), and clean 1/3 of the substrate during during a standard water change every 6-weeks (using a python). This approach minimizes disruptions for my fish and keeps my gravel from compacting with detritus.

 

[charliebankston]

How you change water, depending on your configuration, is important as well. We have a 125g long (about 72in wide), and clean 1/3 of the substrate during during a standard water change every 6-weeks (using a python). This approach minimizes disruptions for my fish and keeps my gravel from compacting with detritus.

Good point! How and why you change. For example some fish are more sensitive to water parameters being a little bad. We change our 125g about 25-33% weekly because it houses discus fish

 

[Mr. Overfilter]

I'd love to keep Discus. I understand that they're fond of brackish. True? But I had no they were inherently sensitive. I saw a video where this REALLY enthusiastic euro-guy built a very fancy aquascape (he even built the tank itself, with SS lily pipes on two filters, AAA decorations and live plants, suspended lights, etc.) that ended in the addition of 6 beautiful discus.

 

[charliebankston]

Oh wow, that sounds nice. We keep ours in regular old treated tap water. Lots of driftwood in there to help lower the ph. They spawn often, but they never hatch. A breeder recently told me they'll only produce live young in Ro water. We don't really want fry anyway. I've found that some of the things they say about them aren't really true. Like they don't like currents or bright lights. Mine never flee when I turn the light on, and they often sit right in the power head stream, lol. We have 11 in there. With 2 female angels and an electric blue acara. They all cohabitat great. 4 of the discus are imported Stendecker. I bought them from a guy who was selling them to get out of fishkeeping. Otherwise I could never afford those

 

[Caliban07]

You should change water based on what your Nitrate level is. Keeping it under 80 ppm is the target. I do 50% water changes every 4-5 weeks. Been doing that for over 10 years now. Some info here for you.

https://aquariumscience.org/index.php/5-7-1-water-changes-in-depth/

Awesome, my tank has 0 nitrates. That means I don’t need to change water. [emoji2]

 

[tmhoskins]

Watch your nitrates after it's cycled and keep them under 40 ppm. And the detritus in the tank. That'll govern how often and how much is necessary. The other numbers you mentioned are just basic guidelines. Every set up is different. Like I said, at least 25% on every change tho

So then how often do I need to do a water change while I am cycling? I bought fish before I knew about all this. I changed about 50% of the water yesterday based on the sticky here and the water got cloudy again, however we did lose some fish so I think the ammonia was high. I got ammonia testing strips to keep track of that but the sticky still said change 50% of the water twice a week while cycling with fish in the tank. Any advice?

 

[charliebankston]

Yeah, that's prob about right. The more fish your using to cycle the faster the ammonia builds up of course. I use a biological liquid booster when cycling too, lots of ppl say they don't work, but I figure it can't hurt and I've never lost a fish cycling like that

 

[charliebankston]

The cloudiness will go away after its cycled good. Most likely that's just a bacterial bloom and when there's no more food source, that kind will die away

 

[Mr. Overfilter]

They're gorgeous, Charlie. Way to be at the right place at the right time. I looked them up locally. I was amazed that they get more expensive as they get more flashy. I don't loose very fish very often, but loosing one of these babies, at $200+ would have me on the deck in the fetal position. Anything special in terms of filter media/driftwood/substrate? I'm using treated tap as well, at least until I can put together a winning case for RO to use on the family CFO.

Since discus aren't quite as complex as I had thought, I'll look up specifics with my current requirements in mind. I'd really like a discus as a centerpiece, if possible.

 

[charliebankston]

Yeah, I was worried getting them due to the cost etc. My wife really wanted some. It was her birthday present, lol. But they've been easier than I anticipated. They eat pretty much any food, I usually just feed them ocean nutrition brand discus flakes

 

[Mr. Overfilter]

Awesome, my tank has 0 nitrates. That means I don’t need to change water. [emoji2]

It would be great if the end product of the cycle, nitrates, were the only determinate of short and long-term health. I've noticed for years, that fresh and marine stock seem to do better with seemingly unnecessary water changes in general. By this I mean more lively, near voracious appetites', skin health, etc. Being that aquatic life-forms have had millions upon millions of years to adapt to their environments, it's at least possible that caring for YOUR fish may be more complex than any online etched-in-stone, my-way-you're-stupid screed can convey.

In essence, watch and learn from your babies. I find the hobby to be more fun that way, at any rate.

 

[charliebankston]

It would be great if the end product of the cycle, nitrates, were the only determinate of short and long-term health. I've noticed for years, that fresh and marine stock seem to do better with seemingly unnecessary water changes in general. By this I mean more lively, near voracious appetites', skin health, etc. Being that aquatic life-forms have had millions upon millions of years to adapt to their environments, it's at least possible that caring for YOUR fish may be more complex than any online etched-in-stone, my-way-you're-stupid screed can convey.



In essence, watch and learn from your babies. I find the hobby to be more fun that way, at any rate.

Ha! Good point!

 

[Mr. Overfilter]

Ha! Good point!

I think so.

View attachment 318615

My observations of this intelligent beast changed my view of meat eating and changed my life in many other ways as well. I wish you guys could have seen her eat a Brazil nut. It was like watching an expert juggler do his magic, underwater. Very messy for a tank, though. She would eat her own dung which seemed to super-charge her growth rate. She almost doubled in size after 18-months.

Edit: my attachment didn't work, and tbh I'm tired trying to figure out picture posting here, for now at least. The pic is of my large head next to my rescued pacu. I lost a good job for this fish, and don't regret it at all.

 

[fishwonder]

I think so.

View attachment 318615

Edit: my attachment didn't work, and tbh I'm tired trying to figure out picture posting here, for now at least. The pic is of my large head next to my rescued pacu. I lost a good job for this fish, and don't regret it at all.

Use the Go Advanced button to post a picture. Then use the Paper Clip icon.