Cleaning

[Morrgan]

I have occasionally seen it said that the amount of water you need to change depends on how many plants you have. The more plants, the less water you need to change, as if plants had some way of purifying the water. This sounds a bit strange to me, but since the topic of water changes has come up I thought I'd ask: is there any truth in this?

 

[Cian McLiam]

Morrgan,
Yeah, plants use some of the waste products of fish and filters as fertiliser, and the roots keep the gravel 'sweet' and prevent anerobic compacting,if there's enough of em of course!

BTW, I also prefer small frequent water changes to large weekly ones. Tap water IMO is too 'raw' and treated for fish. Sorry no chemistry degree here, just observation. If I had RO water I would probably do larger water changes more frequently as you have control over whats going in, the PH, Nitrate and Phosphate levels. In the discus farms in the far east they do 50-100% changes a day even with young discus. They have found they are more resistant to disease and grow quicker.
However, if you dont have the time, or the control over the water, once a week may be better. Clean, consistent conditions are what fish need as water in nature doesnt change that much except during spawning season, when more rain or more heat triggers the fishes instinct that food will be more plentiful in the floods.
Also, I have heard many times that its a myth that water changes temp at night, in large bodies of water, or fast moving streams, the water doesnt change temp much at all, in the waters where discus live it almost never varies.


Ken

 

[Alien Anna]

I have occasionally seen it said that the amount of water you need to change depends on how many plants you have. The more plants, the less water you need to change, as if plants had some way of purifying the water. This sounds a bit strange to me, but since the topic of water changes has come up I thought I'd ask: is there any truth in this?

If your plants are healthy then they do absorb many of the chemicals from the water that could potentially harm your fish, but plants too benefit from water changes.

Dying or dead plant material gives off a plant hormone called ethylene. If too much ethylene builds up in your tank it can cause all of your plants to rot and may also affect your fish. One good argument for shrimps and snails but this doesn't totally cure the problem and even the healthiest of plants will have some die-back.

 

[Morrgan]

Ah ok, thanks for clearing that up.