KiwiGal77 Posted April 14, 2015 Report Share Posted April 14, 2015 My planted tank currently has quite a low bioload, and I'm finding that when I test my levels before my water changes they are all really good - 0 ammonia & nitirite, 0-5 nitrate. I've been doing weekly 30% water changes anyway as it's recommended, but just wondering if they are necessary? Are water changes solely to keep nitrate levels down in established tanks, or is weekly fresh water always required anyway to keep the tank habitat healthy for the fish in other ways? Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted April 14, 2015 Report Share Posted April 14, 2015 If you tank has lots of well developed plants and not much bioload you will be able to do less water changes and the plants will probably like it. Quote Link to comment Share on other sites More sharing options...
Ira Posted April 15, 2015 Report Share Posted April 15, 2015 Are water changes solely to keep nitrate levels down in established tanks, or is weekly fresh water always required anyway to keep the tank habitat healthy for the fish in other ways? There are a lot more chemicals and wastes in the water than nitrate that plants don't remove. Would you be happy to swim around in a septic tank even though a nitrate test comes back 0? Quote Link to comment Share on other sites More sharing options...
Rouseabout Posted April 15, 2015 Report Share Posted April 15, 2015 A septic tank with zero nitrate? Maybe when brand new.... :rotf: Quote Link to comment Share on other sites More sharing options...
Likoma Posted April 15, 2015 Report Share Posted April 15, 2015 A good water change regime is a very important factor when keeping fish. . Imagine living in a glass house on a tropical island with both of the available windows tightly shut. Evey time you do a water change you open those windows and let in lovely fresh air. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted April 15, 2015 Report Share Posted April 15, 2015 A tank with only a few fish will not have the same bioload as a tank the same size containing 20 times as many fish. Quote Link to comment Share on other sites More sharing options...
David R Posted April 15, 2015 Report Share Posted April 15, 2015 I agree with Ira, there is more to it than nitrates. I change ~25% weekly despite only registering ~5ppm nitrate (I can skip a week and it still won't get to 10ppm). You can certainly change less water with a lower bioload, or the same sized change less often, but I don't think its a good idea to give it up all together. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted April 15, 2015 Report Share Posted April 15, 2015 In my opinion the bioload determines the frequency and volume of water changes required not the habit of doing it weekly. When I was breeding lots of fish and had many tanks very heavily stocked it would not have been out of the question to do 80% water changes every other day but in lightly stocked tanks it could be 3 or 4 weekly and a lesser amount. If what you are doing works well for you that is great and everyone else will need to work out what works well for them. Quote Link to comment Share on other sites More sharing options...
Godly3vil Posted April 15, 2015 Report Share Posted April 15, 2015 Water changes are necessary to also replenish trace elements that fish, plants and bacteria use, not just removing nitrates. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted April 15, 2015 Report Share Posted April 15, 2015 I agree but my point was that the frequency and degree of water changes is related to how many fish are in the aquarium. Quote Link to comment Share on other sites More sharing options...
Caryl Posted April 17, 2015 Report Share Posted April 17, 2015 I would experiment and see if you note any changes. Quote Link to comment Share on other sites More sharing options...
Dr A Posted April 19, 2015 Report Share Posted April 19, 2015 To be fair, some proponents of the Walstad methodology essentially don't do "regular" water changes, mostly top off's to account for evaporation. Quote Link to comment Share on other sites More sharing options...
Caryl Posted April 19, 2015 Report Share Posted April 19, 2015 I will probably be criticized for this but I did a water change on my tank before we went away on the 7th April. I think it was the 2nd water change my tank has had this year. It mostly just gets topped up. It is chock full of plants and has a low bioload of fish. Ethan Rose 1 Quote Link to comment Share on other sites More sharing options...
Ira Posted April 20, 2015 Report Share Posted April 20, 2015 I will probably be criticized for this but I did a water change on my tank before we went away on the 7th April. I think it was the 2nd water change my tank has had this year. It mostly just gets topped up. It is chock full of plants and has a low bioload of fish. Quote Link to comment Share on other sites More sharing options...
KiwiGal77 Posted April 23, 2015 Author Report Share Posted April 23, 2015 Thanks everyone for your replies, very interesting Sounds like there's definitely some differing opinions on the necessity of frequent water changes. Will stick to doing small weekly changes regardless of nitrate levels, just to get some fresh water in there. I'm finding my main reason for doing water changes is to suck up any loose plant matter which is hanging around rotting or attached to the filer intake. Alanmin - can you please explain why the plants would like less frequent and smaller water changes? Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted April 23, 2015 Report Share Posted April 23, 2015 they are feeding on the nutrient that you are removing with water changes. Quote Link to comment Share on other sites More sharing options...
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