Why do weekly water changes?

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Gsdsar

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Ok, so this is probably a stupid question. I do at least a 25% WC once a week. I also test my water once a week.

Every week my parameters are perfect. 0 amm, 0 nitrItes, and 10-20 nitrAtes. It's planted.

So if that's all good, why can't I just top it off?
 
If your nitrates are at 20ppm and you do a 25% water change your nitrates would be at 15ppm. You retest the following week and nitrates are back at 20ppm. So your tank is creating around 5 ppm a week in nitrates. If you left it another week with no wc it would be 25ppm. Week after that 30ppm... And so and so on. I would think your fish would be starting to feel and show the effects of bad water after a month of no wc.
 
Your nitrates will continue to build up. Your water only stays in check because of the wc's your doing. After a month or so you would be at 40ppm nitrates give or take a water change or 2, I only used 20ppm as it is a nice round number to work with. Maybe you should try going 2 weeks and see where your nitrates are. If they are too high you can recover with a 50% water change.
 
See I knew it was a simple question! Thanks for the quick response. I may try to stretch it out for 10 days, see how it is, if its okay then maybe push it back.

Thanks again
 
You are making a mistake...water changes 3-4 times per week is the right thing to do. Think of it this way...the filters, pumps, media, air, bacteria etc in your tank function as a giant kidney. Kidneys in Humans filter blood and remove toxins. There toxins are passed from the body in the form of urine and feces. You drink liquids and your body takes what it needs...it disposes of the rest. In the case of the aquarium the waste have nowhere to go. The filters, charcoal, air, bacteria etc all help, but they can't do it alone. There is a lot in your aquarium water both good and bad. The only way to get rid of the bad is through frequent water changes...otherwise toxins build up in the aquarium leading to distress and later disease and finally death in your fish. Think of yourself drinking Vodka all day every day. In no time at all, your body would be full of toxins leading to organ failure and death. are you asking your fish to do the same thing? Toxins are flushed from the body with water. Water hydrates, nourishes, dilutes, flushes and regulates. In your aquarium (kidney) it does the same thing. I do water changes 4-6 times per week....I NEVER have water quality problems or fish disease / death. After over 20 years in the hobby, the one thing I have learned and an absolute....everything goes back to water. Water is where you can do the greatest benefit or the greatest harm.
 
Nitrates are not the only thing that builds up in a tank without water changes. The nitrates might be low but who's to say that other toxins that you can't test for aren't building to dangerous levels. IMO it's best to change more water than you think is necessary to ensure you are providing optimum conditions for your fish.
 
I see people here are kinda making it complicated for you. I have a planted tank so I have to add nitrates to keep the plants healthy. So according to the whole nitrate thing I wouldn't have to so a WC ever. But organisms in the water also build up in the water, like ich and things that cause water blader infections and such. I left it for a month one time and I lost 2-3 neons to infection.
 
There is some good advice in this thread. The water can't be too clean, and changing more than the minimum, as suggested by the nitrate level is cheap insurance against future problems.As mentioned, there are all sorts of toxins and pathogens that build up over time, that don't show in tests for nitrate. A planted tank may show almost no rise in nitrate or even 0 nitrate. There are still organic compounds present that would be better removed. we don't have to know what they are or how much there is. we do know that clean water is the key to long term success in the hobby.
 
So do lots of people do WC 4-5 times a week. That seems very excessive to me. But I will stay doing to once a week. My fish are healthy and thriving.
 
If your fish are healthy why change. I do 2 60% wc's a week on my 125 gallon and as stated there is more to water than nitrates. Nitrates are the biggest toxin you remove but there maybe others and you replace minerals as well. If your understocked and heavy planted I still feel you may be able to stretch it more if your fish don't mind. More is always better though.
 
I have Discus...that is the standard. I can do a 20 gallon WC in about 15 minutes. I do 4 WC per week or about 80 gallons out of 135. That gives me an average of 54%. That is about right for a Discus tank.
 
So do lots of people do WC 4-5 times a week. That seems very excessive to me. But I will stay doing to once a week. My fish are healthy and thriving.

I would not say that 'lots of people' follow hefty water change schedules but I think if you spent some time talking to breeders or those with senstive or difficult fish, you will find this is a common practice. For example, the majority of goldfish breeders will change 100% of the water daily and do not even bother with cycling. For a hobbiest, this isnt realistic or practical. I think you will find the larger majority of people follow atleast a @50% once a week schedule, if not more depending on their stocking.
 
I would not say that 'lots of people' follow hefty water change schedules but I think if you spent some time talking to breeders or those with senstive or difficult fish, you will find this is a common practice. For example, the majority of goldfish breeders will change 100% of the water daily and do not even bother with cycling. For a hobbiest, this isnt realistic or practical. I think you will find the larger majority of people follow atleast a @50% once a week schedule, if not more depending on their stocking.

I agree a 50% water change once week is pretty good for most tanks. If it comes to a point that you need more than that you are overstocked IMO.
 
Thanks! I am in the process now of fish in cycling my new Betta tank. That's been a daily 75% change. He is so happy after I change it!! I think I M going to keep doing the weekly changes. I adore my fish and would hate for them to be uncomfortable.
 
Thanks! I am in the process now of fish in cycling my new Betta tank. That's been a daily 75% change. He is so happy after I change it!! I think I M going to keep doing the weekly changes. I adore my fish and would hate for them to be uncomfortable.

I've got a couple of Bettas in cycling tanks myself. On my established tanks, I do weekly 50%+ water changes with no problems, it usually ends up being more like 70%+ because I get focused on vacuuming & not paying attention to the water being sucked out. :-o
 
Is there an easier way to understand the nitrates and ppm? What does ppm even mean or stand for? I want to learn how to measure water quality and testing
 
So do lots of people do WC 4-5 times a week. That seems very excessive to me. But I will stay doing to once a week. My fish are healthy and thriving.

Every other day 25-75%. My fish have never looked better.

IMO simplest way to explain it is a litter box.
Keep adding kitty litter to the box, nothing bad would be taken out, just covered up and added to.
 
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