Why change aquarium water?

  • #1
Just out of curiosity - if the tank has cycled and water chemistry parameters are good (0,0,10) why do a water change? The reason I see most often to change the water is to reduce ammonia, nitrites or nitrates. If those values are good, then why change the water?
  • #2
Cuz poop builds up and if I were a fish I wouldn't want to swim around in poop...it would stress me out and make me sick..I'm sure there is a more technical answer but that is mine
  • #3
If you don't it will be over come with all the and waste...kinda like not flushing your toilet for a week. Yuck.
  • #4
also, eventually, the nitrates will go up, if it isn't cleaned out
  • Thread Starter
  • #5
OK, that makes sense, but doesn't an increase in poop or waste usually manifest itself in increased water parameter readings? I'm not trying to stir up poop, just playing devil's advocate, and trying to understand why we do routine changes when readings are normal.
  • #6
after a while it will..you want to avoid that. When I get lazy (which happens more then I would like to admit) and I don't do a weekly water change the nitrates go up...this is what you want to avoid which is why you want to do the changes. it's more of a preventive measure..kind of like how instead of getting hepatitis you go and get vacinated for it..prevention is a lot easier then curing the disease later on.
  • #7
no worries, =) Aside from keeping your fish happy cause they are no longer living in grossness , we do them regularly so that your readings stay normal. When it gets bad, those parameters go outside the normal range, we want to keep them there so as not to stress out our fish or ourselves. cause stress is not good for any of us =)
  • #8
The aquarium is a closed system, so the waste has nowhere to go. Eventually the nitrifying bacteria would get overwhelmed by the ever-accumulating waste and the cycle would collapse.
  • #9
Yes the beneficial bacteria will change ammonia into nitrites and Nitrites into the less toxic Nitrates. If you have live plants they will keep the Nitrates down to a tolerable level BUT... total disolved Solids(TDS) will build up and make the tank very unstable and your fish very uncomfortable. Plus it would look bad after awhile with all that Mulm laying all over the substrate.
Fish Addict
  • #10
Yeah, pretty much, why wait for your tank to get to where the fish are about to die? If it gets that way, it will also be a lot harder than to just do it regularly with a little bit of ammonia...
  • #11
Not only are you aiding in the chemistry of your tank its the closeset to giving them a "rainfall" that you can. It is refreshing to the fish in the tank. If you do weekly water changes for your fish, watch your fish the day you do your water changes they are very happy the day you do your change. (I actually at least do 2 waterchanges a week on all of my tanks).
  • #12
I do know of instances where people have developed an ecosystem within their tank that is efficient enough to not need water changes except a couple times a year. The water is clear, the fish are active, and yes, they have a TON of plants. My own tank has been set up for about 2 1/2 months. I have a good number of plants in it and have had steady water readings of 0 ammonia, 7.0-7.2 pH, 0 nitrites and 10 ppm nitrates. If you have live plants in your tank you NEED some nitrates. Still, 5-10 ppm nitrates is very low. API recommends nitrate readings below 40 ppm. I have neons and a yo yo. I know yo yo's can be sensitive to water quality and my little guy has been thriving-and growing so I must be doing something right. I am intrigued by your comment though Steveangela1 so I think I will do a water change and see if my fish 'act happier.' If they do I will definitely change my mind about water changes. I think Aquarium USA had an interesting article on self-sustaining tanks in recent months--the author put their tanks in the window!
  • #13
Another reason to change water is because even with our cute little bubblers, water does become oxygen depleted, which is necessary for the bacteria AND fish to exist. If you limit the oxygen, the cycle will also fail. The lack of oxygen allows anaerobic bacteria to build up, and unless you have a filter set up specifically for changing nitrate to nitrogen and expelling it, you don't want that kind of bacterial buildup. This is the reason to 'stir' your gravel or have MTS snails to keep pockets of nitrogen from building up in your gravel....NEED THAT OXYGEN!
  • #14
before everyone thinks I'm a completely derelict fish owner I would like to add that I still do daily and weekly upkeep. I remove any uneaten food before it has a chance to decompose, clean the inside glass, remove algae from my heater and filter, top off water from evaporation etc. etc. ...and check water parameters at least twice a week.
  • #15
Cool. Yea, I know if you can get a hydroponics thing setup just right and have everything in balance, you can turn the closed system into a partially open system.
  • #16
Just something to think about, are the minerals that are replaced with each water change being replaced if your not doing water changes?
A lot is added with the food etc, but if you use a low grade food, are the fish getting what they need?
  • #17
They may not be, so we get the better quality foods for them.
  • #18
There is a guy on another fourm that does do a self sustained fishkeeping method.. and it does work for him... so yes it is possible... however, you should research it before you try it. Make sure you use plenty of plants. That was his method. He also did loads of reasearch and posted his research on that forums page (talking about something that was like a doc degree project! wow! well detailed!)

I have to say this person has done this since the 70's and obviously reading his post, and research.. he has more than high school chem/bio classes or he is just really into studying this stuff!
  • #19
Are you into plants? Then maybe you should consider this.

After reading up and doing some research I am beginning to find an approach that I like. I just planted my first Naturally Planted Tank. I used ~ 1 inch of topsoil and covered it with ~ 1 inch of gravel. I planted several Wisteria and Crypts. I have the tank near a window where it will get a couple of hours of sunlight each day. Fish waste and fish food become your fertilizers for your plants. Depending on what you have planted in the tank and the tanks parameters you may only have to do waterchanges every few months. I don't have any plans to add fish until I know the water parameters are fine. I have Diana Walstad's book on order and can not wait to read what she has to say. I can't wait to see where this is going to go.
  • #20
Quite an interesting thread.
  • #21
If you have a tank set up using the Walstad method, there really is no need to do water changes unless there is a problem like a sudden illness or if the plants an/or fish don't look happy. The plants use the fishie poop and uneaten foods as fertilizer.

If you ever decide to set up any tank like this, I strongly suggest you read Diana Walstad's book first so you understand everything because there is a lot you need to know about this type of set up and it's best to educate yourself first before just diving right in.

Both of my tanks are set up this way and I love it because you can enjoy keeping aquariums while conserving water!
  • #22
Ntruder1400 - A friend just had an article published on Dissolved Organic compounds in the aquarium and it explains what goes on in the aquarium and how to lower these so much better than I did


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