Water Changes

[hoyfoys]

Hi,

I have a fairly heavily planted tank which is basically fully stocked, although only 3 months old. I have 12 Amano shrimps and 2 butterfly plecos. Ammonia and Nitrites are consistently 0 and I'm finding that the Nitrate rarely goes up much or if it does then very slowly. Are water changes only used to keep Nitrates low? If so do I only need to do a water change when they get high (above 40ppm?) or are there other reasons to keep doing them? At the moment I'd say that going by the Nitrate levels I'd only need to do a water change every fortnight or maybe even once a month.

Thanks

 

[SchottayB]

I only did water changes once a month too, untill I started using fertz for my plants (I hear doing one a week is better all round). For someone not using fertz and what not I'd also like to see what the point of water changes are if your stats are fine

 

[K_Hedin]

I stopped doing water changes on my planted tanks because my stats were always all 0. However after a month and a half of just top offs my plants started to not look so hot. There are a small amount of minerals in the water that the plants will use up and then they will no longer be present. While it may not seem necessary, it is still a good idea to do a WC. At least that is what I have found, through the help of a member on this board.

 

[fishguy2727]

Water changes do many things. Nitrate is focused on so much because it usually correlates with all the other bad things that can buildup (growth inhibiting hormones, dissolved organic compounds, etc.). However, in a planted tank the nitrate has an output (the plants) but the other bad things do not. This leads to them building up even though the nitrate is fine (I would keep it under 20ppm).

The other major function of water changes is providing things in the water (KH, GH, other minerals, etc.). KH goes down over time in any aquarium. Live plants can actually use it as a carbon source if there are no better options (CO2, liquid carbon supplements, etc.). Without water changes or other supplementation to keep all these things in the water, they will diminish over time and neither the plants nor fish will do as well.

The good thing is that water changes in a planted tank do not usually need to be done as much as other tanks. I would still do them weekly, but they may only need to be about 10%.

 

[KkAaNnEe]

Very good an detailed answer above. The only thing I would add also is if your tank is bigger, you can get away with less frequent changes, but stocking is the major factor too, lightly stocked, every two weeks would be fine, just up the percentage to 30%-40%

You could do it every month if you want, i just like the satisfaction of doing it, always seems like my fish appreciate it.

Oh, also, wc's are good as it also acts as dedicated time when you can do maintenance etc such as siphoning, cleaning, filter maintenance...

 

[hoyfoys]

Thanks guys, a big help

I had wondered if doing a water change less often was helpful as it seems to spooks the fish a little.

 

[fishguy2727]

It shouldn't be a stressful thing for them. What do you mean by spooked?