Daily water change vs weekly

[The Doug]

I don’t even know where to begin… okay so If I have a 240gal planned tank full of Val loaded with guppies and small tetras  (tank size 49x29x39) would It be more beneficial to switch to daily water changes when I already have a solid weekly schedule? (Also keep in mind I’m wanting to put a Mbu in for his grow out tank ) and if switching to daily water change should I automatically dose fertilizer each day? This is where I get confused also I have a 55 gal sump and 55gal reserve if that helps never test over 10 ppm nitrate end of week.  I could just use some input 

[The Doug]

@AnimalNerd98 I have no real

reason for the change other than to do something different I suppose I’ve heard Mbu puffer are highly sensitive to nitrates so possibly I need more research on my end but I’m going for big picture I suppose .. i could potentially increase ferts going into the tank also  my plants have all grown  maybe they need more but I struggle getting over 10 and if I go over a week the tank is noticeably dirtier than weekly (overfeed for baby’s in tank ) 

[Flumpweesel]

Most people strive for less not more water changes.

I wouldn't recommend daily unless I had a problem with the water my tanks all go 6 to 8 weeks between changes I just do them when the tests tell me to.

If it's just about removing the poo then you can make (some one in here has a DIY one) or buy syphons that pass the water through a filter sock then return it to the tank. That might be less disruptive and waste less water in the long run.

I have also seen people use power heads or wave makers on a timer to stir up the tanks and get the waste into the filters although that might be tough on guppies 

[Flumpweesel]

I should add the reason I wouldn't is because the bacteria we depend on to keep the tank safe grow based on amount of food available to them all those changes could end up with a tank that is biologically uncycled (certainly not seasoned) and if you where to go away for any reason and had to miss one or two changes this tank could crash.  

Pushing water changes back helps create a stable environment. 

And where it is pretty easy to get someone to nip in daily to feed fish to change water you are calling in much bigger favours.  I know that if anything happens to me my tanks can wait for me to get back the algae might be a mess but the fish will be just fine. Because i have a high background of bacteria even if it was left an additional month or so the existing bacteria will be able to keep up easily.

 

[Mmiller2001]

On 8/10/2022 at 12:44 AM, AnimalNerd98 said:

Doing too many water changes can actually stress out your fish and shorten their lifespans.

Careful here, as this is completely untrue. I and many others are doing 90% water changes weekly. Large water changes is a benefit to a planted tank and in fact keeps a more stable tank. If you look at the top AGA tanks, those are probably getting 90% changes 3 times a week. You just have to know your source water.

Also, 20 to 40ppm NO3 on a non CO2 injected tank is too high. I would aim for 12 to 18ppm NO3 as proxy. Fertilization is more than just NO3. Make sure your are dosing comprehensively. 

I would go 50% per week. Just do yourself a favor and learn how to make these water changes not so much work. I.E. using water storage and pumps.

[lefty o]

a 240 gal tank with sump, you can go a long time between water changes if the tank is running well. the bigger the tank, if things are good, the longer you can go between maintenances.  the daily and weekly water changers would lose their minds if i told how long my 120 typically goes between changes, and it doesnt have a sump, just 2 ancient HOB's.

[AnimalNerd98]

On 8/10/2022 at 9:53 AM, Mmiller2001 said:

Careful here, as this is completely untrue. I and many others are doing 90% water changes weekly. Large water changes is a benefit to a planted tank and in fact keeps a more stable tank. If you look at the top AGA tanks, those are probably getting 90% changes 3 times a week. You just have to know your source water.

Also, 20 to 40ppm NO3 on a non CO2 injected tank is too high. I would aim for 12 to 18ppm NO3 as proxy. Fertilization is more than just NO3. Make sure your are dosing comprehensively. 

I would go 50% per week. Just do yourself a favor and learn how to make these water changes not so much work. I.E. using water storage and pumps.

Thanks for correcting some of the vagueness of my answer. I hid it so that I can prevent myself from spreading misinformation. You are absolutely correct that it depends on the source water, but water changes can stress out fish depending on the temperature change, speed at which water is blasted in, etc. But I cannot find any sources on it shortening the life of fish, that was an incorrect extrapolation. 

Second, according to the Co-Op article on nitrates, 20-40 ppm is within a safe range.
"We personally recommend keeping less than 80–100 ppm nitrate in your fish tanks."
"Therefore, we aim to keep approximately 50 ppm nitrate in planted tanks."
Source included: https://www.aquariumcoop.com/blogs/aquarium/nitrate

Edited August 10, 2022 by AnimalNerd98

[Mmiller2001]

On 8/10/2022 at 12:29 PM, AnimalNerd98 said:

Second, according to the Co-Op article on nitrates, 20-40 ppm is within a safe range. Source included: https://www.aquariumcoop.com/blogs/aquarium/nitrate

Don't hide it, just add could be. 

Research has shown even higher on Nitrates, I'm referencing lower numbers do to potential algae issues. It's just not necessary to be so high especially when not injecting CO2. I kind of fall into, "just because you can, should you." I've also found, while trying varying approaches to fertilizing, that leaner run tanks do a bit better. That said, others run full EI dosing and do quite well.

[nabokovfan87]

I will triple check the posts above, but I wanted to mention a method based on the OP.  WHY you would want to avoid daily changes and perform larger water changes.
 

Essentially, Let's say you're doing a "flow through" type of setup.  Water is always flowing into the tank and you have an overflow (or weir) and you're trying to use that as your main method.  Typically what you would see is that the overflow goes to the sump. To remove water you'd have a pump to the floor drain or a tube that goes to the drain or you'd turn on the valve to drain water.

SO.... let's assume "best case scenario" and that you have a flow through concept. 4 ft tank, input on one end and output on the other end.  Water might have the striations based on temperature or some other parameter and some portion of your new water is going to go from the input, float across the top, and flow out.  Using wavemakers or pumps would push things around and mix that up, let's assume that's the setup.  It's hard to "know" what amount of water you're truly changing.  The slower the flow (or using a spraybar to randomize the output pattern) would help to keep things mixed as best as possible and force the pumps/equipment to churn things up.  What you really want is something that flows in and then the junk flows out, but it's not that simple.  

This is where big water changes, less often, can be beneficial.  This gives you a chance to go in and remove the muck, target the waste, clean things up, and have a bigger impact on water quality.  There is some interesting stuff by the Monterey Bay Aquarium regarding their care of great white sharks (not recommended, please don't do this!) and it actually focuses pretty well on this issue. A LOT of sharks don't pump water over their gills.  The breathe by swimming and swimming too slowly or not having enough flow actually causes deaths. They have records on how long they've been able to keep sharks alive, and it's a real bad time for those who cherish the species to see them suffering in this way.   We are learning things by doing this, but it's very difficult on the fish and they will never really be able to be kept in a zoo/aquarium...... because they don't have this magical flow through system with constant 0 nitrates.  Because they can't have the same dilution as the ocean, the same flow as the ocean, and it's so difficult to replicate that specific instance, that is why you run into such issues in that environment.

If you wanted to have a best bet in terms of the overall design of a tank like this, river tanks is where you'd be able to get close. The amount of water flowing in is very high and the tank drains on the opposite end.  You don't have water being removed, but that method for moving water on a massive scale is sort of where this goes.  To try to replicate this at home I would imagine that flowing water into the tank, then that goes through the filtration, before it gets pumped back through into the tank, part of that water is siphoned out at the same rate from the sump.

 

On 8/9/2022 at 11:00 PM, The Doug said:

okay so If I have a 240gal planned tank full of Val loaded with guppies and small tetras  (tank size 49x29x39) would It be more beneficial to switch to daily water changes when I already have a solid weekly schedule? (Also keep in mind I’m wanting to put a Mbu in for his grow out tank ) and if switching to daily water change should I automatically dose fertilizer each day? This is where I get confused also I have a 55 gal sump and 55gal reserve if that helps never test over 10 ppm nitrate end of week.

I would hope the plants keep things stable for you, especially in that tank.  I would keep things weekly or 2x a week at most just to keep things stable. Dosing weekly, several times a week, etc. is going to be determined by the algae and tank parameters.

[modified lung]

On 8/10/2022 at 8:53 AM, Mmiller2001 said:

Careful here, as this is completely untrue.

It's true to a degree. Big, frequent water changes and over filtration can under develop the immune system. That doesn't necessarily mean they're lifespan will be shortened. But it does mean they'll be more susceptible to disease especially when exposed to other stressors. In which case their life span can technically be shortened. Cory actually mentioned a little about this in the live stream after Germany. Basically, a lot of breeders and wholesalers operate in a way that creates fragile fish for their customers.

[Mmiller2001]

On 8/10/2022 at 6:23 PM, modified lung said:

It's true to a degree. Big, frequent water changes and over filtration can under develop the immune system. That doesn't necessarily mean they're lifespan will be shortened. But it does mean they'll be more susceptible to disease especially when exposed to other stressors. In which case their life span can technically be shortened. Cory actually mentioned a little about this in the live stream after Germany. Basically, a lot of breeders and wholesalers operate in a way that creates fragile fish for their customers.

Interesting, river fish get 100% water changes every few minutes. 

I'd imagine many breeders are using tap water with parameters not native to many of their fish. Here I agree it weakens fish. I will fall back to knowing your source water. 

[modified lung]

On 8/10/2022 at 7:24 PM, Mmiller2001 said:

Interesting, river fish get 100% water changes every few minutes.

Well, not really. Rivers don't have their water drained every few days and replaced with sterilized or treated water. The new water from upstream brings it's entire ecosystem of micro and macro organisms with it. That kind of stuff is important to fish. Maybe less important to plants? You know way more about plants than i do.

[Mmiller2001]

I'm just saying that water changes, made to match parameters of the outgoing water, doesn't harm fish in any way. Add to that, the reduction of organics, replacement of macro and Micro elements is an overall good thing for plant and fish health. I also believe going to no water changes, Diana's method, is an excellent way to go as well. Personally, it just seems easier to clean such a large tank when the water is reduced by half. Also, water changes are way cheaper than spending a lot of money on cleanup crews and testing if doing small or no water changes 😁.

[gjcarew]

On 8/10/2022 at 8:29 PM, modified lung said:

Well, not really. Rivers don't have their water drained every few days and replaced with sterilized or treated water. The new water from upstream brings it's entire ecosystem of micro and macro organisms with it. That kind of stuff is important to fish. Maybe less important to plants? You know way more about plants than i do.

A lot of rivers do have very clean water since they are usually rain or snowmelt fed. Most of the microscopic life in rivers is concentrated in aufwuchs communities.

That said, it also depends on the quality of the water one has available for water changes. Here in the PNW we generally have soft water, so I would do smaller water changes for hard-water fish like livebearers.

On 8/10/2022 at 5:23 PM, modified lung said:

It's true to a degree. Big, frequent water changes and over filtration can under develop the immune system. That doesn't necessarily mean they're lifespan will be shortened. But it does mean they'll be more susceptible to disease especially when exposed to other stressors. In which case their life span can technically be shortened. Cory actually mentioned a little about this in the live stream after Germany. Basically, a lot of breeders and wholesalers operate in a way that creates fragile fish for their customers.

Cory has an interesting theory here, but I don't know if I buy it. Wild-caught fish can be significantly more fragile and prone to sickness than farm-raised fish. To the degree that there is weakness in farmed stock, I would be willing to bet that inbreeding is a much bigger issue than well-filtered water. 

[face]

the argument of small water changes or large has been going on for literally decades and i don't think its going to stop soon

that said i think it depends on what you are doing in your tank if you are keeping guppies and buffering your water with crushed coral for example small frequent water changes might be for you if you are a cichlid keeper fighting the groundhog day war against nitrates large water changes make sense if you want to do automatic water changes a small frequent ones is generally how those work if your tank is getting physical dirty between  changes do smaller more frequent changes

choose the one that works for your tank lifestyle and wallet given the hundreds of variables in an aquarium the trying to tell the difference between small and large water changes on fish health is going to be nearly impossible so i would just do what makes sense off tangible thing you can see or test for well that's my opinion anyway.

[modified lung]

On 8/10/2022 at 8:50 PM, Mmiller2001 said:

I'm just saying that water changes, made to match parameters of the outgoing water, doesn't harm fish in any way. Add to that, the reduction of organics, replacement of macro and Micro elements is an overall good thing for plant and fish health. I also believe going to no water changes, Diana's method, is an excellent way to go as well. Personally, it just seems easier to clean such a large tank when the water is reduced by half. Also, water changes are way cheaper than spending a lot of money on cleanup crews and testing if doing small or no water changes 😁.

Can't argue with any of that. I'm not saying water changes are bad. I would be against 90% 3 times a week though. Not because of the chemistry but because the ecosystem of bacteria in the water column is also important. Although, as long as the 90% 3x is kept up throughout the fish's lifespan, it really shouldn't be a big problem. A person that grows up in a sanitized bubble is safe and healthy as long as they stay in the bubble.

On 8/10/2022 at 9:17 PM, gjcarew said:

A lot of rivers do have very clean water since they are usually rain or snowmelt fed. Most of the microscopic life in rivers is concentrated in aufwuchs communities.

Sure but all natural waters also have a suspended bacterial and viral ecosystem that is important for life. Even rain droplets aren't sterile.

On 8/10/2022 at 9:17 PM, gjcarew said:

Cory has an interesting theory here, but I don't know if I buy it. Wild-caught fish can be significantly more fragile and prone to sickness than farm-raised fish.

Wild caught fish generally die from confinement stress or conditions brought on by that stress. Documenting this was actually part of my last job. The stress can be so bad for some their skin falls off.  We had vets do autopsies and disease among wild-caughts was very rare.

[gjcarew]

On 8/10/2022 at 11:41 PM, modified lung said:

Sure but all natural waters also have a suspended bacterial and viral ecosystem that is important for life. Even rain droplets aren't sterile.

Tap water isn't sterile either. I'm not sure there is a significant difference.