How long can you go without a water change?

I am not new to this hobby and I have lots of experience... I do water changes 50% every week depending on how much I feed and if my tank is overstocked/understocked. The question I was wondering was: how long can you go without a water change BEFORE your water starts to reach dangerous levels? Let's assume the tank is heavily planted, a large tank (29 + gallons), and does not have a lot of fish. I know some people have heavily planted nano tanks and do not perform water changes weekly, because of how low maintenance it is. Anyone have experience/information? Any is welcomed, thank you!

 

i feel like if your tank was heavily planted the plants would help with the ammonia big time i would do a water change every 2 weeks but thats just me. i do a water change every 3 days due to my tank being 2.5 gallons plus it has not completed the cycle. i tried my best hope this helps

 

Haha... I don't have a heavily planted tank but I would love to have one. If it is low maintenance that is a plus as well! I was just curious on how often people clean tanks that are heavily planted, big space, and less fish/invertebrates.

 

Haha... I don't have a heavily planted tank but I would love to have one. If it is low maintenance that is a plus as well! I was just curious on how often people clean tanks that are heavily planted, big space, and less fish/invertebrates.

i feel like if you made a java moss scape that would be pretty cool and some shrimps?

 

I never have luxury of big tank, so can't speak for myself. My uncle used to have a 40 gallon heavy planted Parrot tank with Myrio Green. My uncle only do water change monthly. Mostly to clean up the fish waste to prevent debris build up. The water readings are stably good throughly.

Myrio green really helped. So did the 10 inch substrate for beneficial bacteria to live in. Both took care foul chemical from waste.

 

Depends on so many other factors. With a well balance tank people claim they go years between water changes. I've gone as long as a year without changing water. There are just so many factors. One of the biggest problem is over feeding as decaying food is pretty bad for water quality as oppose to decaying leaves which i suspect actually helps water quality (just because i suspect this is the case doesn't make it a fact).

 

As you're probably aware the first thing to make fish unhappy is the accumulation of nitrogen in the water. There are ways to reduce the rate of accumulation thereby extending out time between water changes.

1) Feed less. Almost all nitrogen over the long term enters the tank as fish food.
2) Increase the relative volume of water & water changes.
3) Store the nitrogen in biomass such as plants & mulm to be removed later.
4) Improve your nitrogen cycle. Particularly, denitrification which requires conditions not typically present in the aquarium in large quantities.
5) Chemically bind the nitrogen (Prime). Not very practical for long term but useful in an emergency.

The low maintenance aquarium likely utilizes some combination of the above. It is theoretically possible to reduce the rate of accumulation of nitrogen to zero without water changes however this would require a very intricate design and still wouldn't eliminate the need for water changes.

 

The longest ive gone is 6 weeks while i went back to aus for a holidsy . That was with top offs every week and the fish only ate what they shrimp they could hunt.

Didnt lose a single fish and my tanked looked better after i came back.

 

I've been getting busier and don't have as much time for weekly water changes. I have mollies, mystery snails, and shrimp in my 10 gallon aquarium with a lot of plants and a penguin filter. Can I go for at least a month without water changes?

 

It depends on the week for me. Sometimes I can go 4 days, sometimes I can go 7. I test for ammonia every couple of days to see where it's at. If it's starting to inch above 0, I'll do a water change. Or, if it hits the 7 day mark, I'll do one then.

 

I would not go that long in a 10g tank. The water can get bad very fast in that small of a tank. I'm sure you can squeak out 15 minutes for a water change somewhere in your schedule.

 

I've been getting busier and don't have as much time for weekly water changes. I have mollies, mystery snails, and shrimp in my 10 gallon aquarium with a lot of plants and a penguin filter. Can I go for at least a month without water changes?

You need to do at least once a week water changes, especially since you have a couple of fish and snails. Snails produce a lot of waste.

 

With high nitrate production, fully stocked, soft water and plenty of media my tanks are limited by depletion of KH. If I boost them up to 5-7 dKH at a water change, I might get 10-14 days. At the normal 3-5 dKH I run, about 7-10 days. When I had lighter stocking it wasn't unusual for me to go 20-25 days, but I have been very carefully building up (natural) nutrients and balancing (added) minerals in my tanks to serve a specific goal over several years.


If I were to put an adult mystery snail and a few common molly in a 10, I would figure my water would support them for a week, and harder water maybe up to two, but it would be limited by other factors. Before I would ever recommend stretching changes from usual, I would recommend the person asking do a ton of tests, and log them for a month or longer to verify usage of available resources vs accumulation of nitrogen byproduct.

If anyone were to be building up ammonia, I would recommend they open a thread and get that sorted out as it's not normal in a cycled tank.

 

With high nitrate production, fully stocked, soft water and plenty of media my tanks are limited by depletion of KH. If I boost them up to 5-7 dKH at a water change, I might get 10-14 days. At the normal 3-5 dKH I run, about 7-10 days. When I had lighter stocking it wasn't unusual for me to go 20-25 days, but I have been very carefully building up (natural) nutrients and balancing (added) minerals in my tanks to serve a specific goal over several years.


If I were to put an adult mystery snail and a few common molly in a 10, I would figure my water would support them for a week, and harder water maybe up to two, but it would be limited by other factors. Before I would ever recommend stretching changes from usual, I would recommend the person asking do a ton of tests, and log them for a month or longer to verify usage of available resources vs accumulation of nitrogen byproduct.

If anyone were to be building up ammonia, I would recommend they open a thread and get that sorted out as it's not normal in a cycled tank.

Agree. Gently rising ammonia has only occurred for me in the twoish weeks following the addition of new fish as the bacteria adjust or if a big plant needs a few leaves pruned at once. If you let it go for a month, the waste in the tank could easily surpass what the bacteria are capable of processing.

 

You need to do at least once a week water changes, especially since you have a couple of fish and snails. Snails produce a lot of waste.

It’s good to ask that now, I have a similar tank. Those occupants all produce a lot of waste. The problem being everyone looks happy and healthy, but then they’ll get disease or one will die for seemingly no reason. The long siphon that attaches to a sink makes a water change job so much easier. You can also clean the filter, substrate and water on different weeks if that helps. Make sure not over feed and your snail needs a cuttlebone for calcium laying about along with it’s food. I hope you find a plan that works for you! happy fishies!