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Minimum Water Change Frequency

11K views 47 replies 21 participants last post by  zerodameaon  
#1 ·
How long can I hold off for a water change until I start seeing negative effects?

I'm lazy and want to know the minimum I can change my water and yet still have a beautiful tank. Open to hearing your experiences and observations. Thanks for sharing.
 
#2 ·
Beauty is in the eye of the beholder! If your standards for what is a beautiful tank are flexible enough, you can avoid any water changes and still have a beautiful tank. You would have to use low light, so you could succeed without fertilizing. You would need to have a low bioload in the tank so natural processes could keep the water suitable for fish. One way to do that is the Walstad method.
 
#4 ·
The answer is no one really knows what is good for your tank except your tank. As an experiment, I completely stopped both dosing and most of the water changes after seeing BBA ruin what was up to that point a beautiful planted tank with a much higher bio load than most. I tried to maintain the perfect PPS regiment with water changes based on TDS but nothing seemed to halt the downward spiral. Aside from a sump clean out which used 15 gallons on a 90 gallon tank, just RO top offs and metricide.

That was June 10th. Fast forward to today and the tank never looked so good. I only recently began to dose again but at a much lower level. If the BBA re-appears, back to lazy.
 
#9 ·
#5 ·
There's no universal answer to that question, it will vary greatly based on factors like lighting, sub strait, plant load, plant types, livestock load, filtration, perhaps even the water chemistry of your municipal system. I've seen tank journals and have read articles on tanks that can go pretty much indefinitely without water changes, but they were set up specifically to run that way, and it's not necessarily a lazy way out as it requires plenty of work in its own right.
 
#6 ·
Too many variables to begin to set a minimum. For started on variables, we have to look at how we each define beautiful. What is a planted tank to each of us? Defining lazy versus enjoying the work? Is it work to change water but not work to test and figure what is needed ?
I have to find the level I like on each of my tanks. I have had as many as 13 tanks at one point and found that was too much work. But each of those tanks required different levels of and types of work. some took lots of water changing, while others took lots of time in testing and changing the routine. Many were bare bottom breeding or growout tanks but that did not mean there was not something that required attention on all of them.
Since we each have a definite personal definition of what is fun and what is not, the answer of what is minimum water change, is going to vary a lot.
A single turtle can go a long time in a very bare tank! It may be a stinking pond for some while the owner may love it.
 
#14 ·
Unfortunately, to a degree, fish (and plants) can adjust to tolerate poor water quality before there are any visible signs. Although if you look closely, you might begin to see some signs of stress (shimmy, flashing, surface gulping, erratic swimming or behavior...)

To a point, we might use nitrates, phosphates, and TDS test results to help identify the need for a partial water change...but by far the easiest method is to do a modest water change at least weekly to maintain a consistent water chemistry that is better for the fish. Waiting for long periods and doing a larger water change could potentially shock the fish.
I am shooting for a Nearly Natural Habitat, so I just do modest water changes to allow the plants to use the organic nutrients and purify the water. I use chemical additives only as absolutely necessary, watching the plants for any cues.

In the end, if you care about the fish, it's better to err on the side of too much volume/frequency of water changes vs. too little. And suffice it to say that for over 50 years, scientists and expert hobbyists have been 'preaching' the merits of partial water changes in fish only AND planted tanks.

Experimentation is great, but we don't need to prove the world is round because we know that to be true.

Wanna have a beautiful aquarium with healthy fish - prepare to spend 1 hour a week for tank maintenance - it's more than worth the effort!
 
#16 ·
I have a 120 gallon that I like to get 50% weekly but often gets 25% bi-weekly, more or less. A newish 75 gets a full 25% every ten days. A 20 that has only got a now and then 20-50% for the last six months. And last is a ten that gets 50% every three days as I dose meds for a sick fish.
The difference is in the tanks. The 120 has my best fish and I should do better but I'm not motivated. The 75 has my current main interest, so it gets the best care while the 20 has nothing but holding a couple of females holding fry and waiting their turn to release them. The 10 is a QT and I would like to save that fish. The med specs doing two treatments, water change and treat, so I want to get the best results from the med. The sick fish came shipped in sick but I mostly try to avoid more sick ones. But I also know that I can do the best at preventing disease if I do water changes! Sometimes it happens, sometimes it doesn't.
 
#24 ·
http://www.plantedtank.net/forums/12-tank-journals/1042170-ada45p-9gallon-cave-tree-1st-tank.html

the op has a terrific thread going re his tank. it doesn't seem like energy or motivation is an issue at all. actually he seems pretty experienced to me based upon that thread.

maybe this thread is just a discussion-starter and not one the op practices. i think most posters on this board are conscientious about their tanks. and perhaps this topic, on it's face, just rubs people the wrong way. i certainly understand the slight pushback but the op's own tank thread shows me he's not practicing the question he's posed above.

my .02

as to my wc schedule, i'm more of a 'fish first, plants second' guy. so weekly wc's tends to the norm for my 3 tanks (caveat, 1 tank of new fish is twice weekly).
 
#32 ·
You don't have anywhere near enough info here to formulate advice with. It is irresponsible to give out advice without enough information. In order to come up with any kind of advice on water changes I should know everything that is going on with your tank, tank size, filter, water parameters, plants, livestock. If you are dosing quite a bit of fertilizer on a daily basis your tank would probably benefit by 50% weekly changes. If you are lightly dosing or not at all it could go considerably longer.

My main tank has not had the water changed for a few months, but I have also almost completely backed off dosing during this time. Some of my plants are suffering slightly, others are thriving. I will say none of my plants are very demanding. The tank still looks good and all the livestock seems happy and healthy
 
#34 ·
While some can get away with seemingly paradoxes, most do not.
They get algae, they overlook things, they make mistakes, some much more than others, most still make mistakes.
I do, but I can fix it them much easier and know what I did to cause them.

Given the OP goal................

An emergent tank, non CO2, rich sediment perhaps, decent algae eating shrimp and fish would work well.
But, they would need to do frequent water changes the first few weeks, regardless of the set up.

If you cannot do that, you signed up for the wrong hobby.

New folks make a lot more mistakes, water changes fixes those and resets the tank.
Telling new folks that you can do it without any water changes this is not a good idea.
Yes, experienced folks, some specific goals and styles/methods can help, but new folks make far too many mistakes.

Still, if lazy is a goal whether you are lazy or not, new or well seasoned: non CO2, emergent growth, good algae eater population, rich sediment, water changes for the 1st one to two months, plant heavy from the start, relatively low light, enough to grow the plants.

Here is one such example I did that met most of the advice I just gave(sediment is inert and the light it high, but blocked from above and I fed the tank pretty well. No dosing of ferts, just fish waste)

 
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#35 · (Edited)
Hi @IntotheWRX,

How about a pic of your beautiful tank? I suspect that you were not doing EI dosing per the recommended schedule during the 18 month period?

I have only been keeping fish for 5 or 6 decades so I don't know a lot. But there is one thing I do know and that is for me to have healthy fish, that grow to their maximum size and beauty, I have to do regular water changes. When it comes to my tanks my primary consideration is a healthy environment for my fish with minimal organic waste and detritus. Weekly water changes help me to attain that goal. I have not yet met a successful fish breeder that spawns and sells fish on a regular basis that doesn't do 1, 2, or even 3 water changes per week.
 
#39 ·
and why you guys deleted my posts?
?????????????????? Maybe one of the other threads you opened this morning? This is the first response from you I have seen in this thread.
 
#41 ·
I have gone months and months without water changes during chaotic times of my life. I wouldn't recommend it but most fish will probably survive. Plants in a high tech situation need more care though (low tech will usually be OK IME).

I wouldn't recommend it obviously. You will over time be more likely to lose sensitive fish if you let the Nitrates get too high and it can lead to problems. Certain fish are more sensitive to it than others. For example in my tetra tank when I would go too long I had Hyphessobrycon sp. HY511 (candy cane tetra) that would develop pop eye when the Nitrates got into the 80ppm or above range. They would usually live with it for a while but eventually it would kill them. I am still not the best at doing water changes but try to do them at least twice a month for all my tanks.
 
#43 ·
Telling people to skip water changes or avoid them all together is a recipe for disaster for 98% of aquarium enthusiasts, and out right irresponsible considering all systems are different with varying levels of demand for cleanliness and maintenance. Honestly, every tank will be different, but best to err in the side of safety than laziness as a general rule of thumb for life and our aquariums. If aquarium maintenance is too much of an inconvenience best to pick another hobby so other living things arent relying on how energetic you feel that day as their health depends on it. Theres more in the water than nitrate, hormones from all the creatures in your tank are mixing in 24/7 and fish require balanced mineral content in the water as well to maintain health and organ function.
I have 42 collapsed joints, 6 slipped discs, 5 permanently dislocated ribs, 2 implants holding my side together, severe osteo arthritis, nerve damage, and my hip is constsntly out by over an inch to name a few things... so I believe I have just as much reason as anyone else to dread physical labor... I still do weekly 50% water changes, why? Not because it is fun, or easy but because its necessary for my EI dosed, high tech, and my low tech planted and breeding tanks to keep them balanced and healthy.
 
#45 ·
Didn't want to reply to this controversial subject but!!!

Having an 80G (claimed to be) no WC tank with plants only.
It still required WC's in the way of vacuuming the substrate periodically.
Snail crap, decayed plant matter, cap breaches, etc... No fish for 6 months.
Some weeks even got a double EI dose of ferts, consumed by the plants.
So many plants TDS was always dropping.

But I still had a reason for removing and replenishing water!
Even with zero "Phish"!

More recent times prompted me to add some baby Cory's.
There only purpose is to stir the substrate, keep things moving about.
Their trivial amount of excreted waste is like me dosing Urea in this uncycled tank.
Plants remove it before it is detectable.