# Science of water change in planted tank?



## David Ash (Jun 11, 2014)

Hello all, fist time post here.

I have 4 Bettas, rotating though various tanks of 2.5, 5, & 10 gallons. All tanks have a hefty chunk of java moss, and I'll be adding water hyacinths in a few days when they finish quarantine. I use tap water filtered with a beefy charcoal filter, treat it for chlorine, then age it for ~24h with crushed indian almond leaves. Hot climate here, so no heaters, and aged water is same temp as old water (~82). I feed mostly live mosquito larva, with some spectrum pellets & fasting.
Fish seem very healthy & vigorous.

Their main stress is from the water changes- I catch them in a glass cup, and then immediately float the cup into the new tank, adding a tablespoon of new water every few minutes until they have mostly new water, then release them. I do it gentle, but they hate it. They hyperventilate, thrash around.

My question is, because there are lots of plants, does anyone have any actual evidence that I need to be changing all of the water at all? If I test the water for ammonia, nitrite, nitrate and it comes up ok, is there any other reason I should do it? Shouldn't it be OK to siphon some crap off the bottom every so often, and never do more than a 50% water change every week or two?

Thank you all for your thoughts, especially for informed opinions & substantiated facts!


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## Briz (Mar 22, 2013)

The java moss is certainly helping with the water quality, but I don't believe they are enough to rely heavily for your filtration (even with a lot of it). Fast growing stem plants and floaters like duckweed are the best absorbers of ammonia and nitrites. Even heavily planted tanks (with a large variety of plants) still require some water changes, as things like pH and kH aren't overly affected by plants.

Do you know if the tanks are cycled? If they are, and you test the water to find good parameters, you certainly don't need to do a water change that day. If your fish seem healthy and happy, and the water is tested good, then you can cut back on the water changes. The smaller of the tanks will still require more frequent changes than the larger tanks irregardless.

Siphoning is a good idea, since you don't have rooted plants that would be disturbed. If you ever do have rooted plants, you can simply hover the siphon over the substrate to pull up the junk but don't do deep gravel siphons near those plants.


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## David Ash (Jun 11, 2014)

Thanks,

The tanks are currently uncycled, unfiltered. I just move the fish, drain 100% of the water every few days/week depending on size, then wash the tank with a clean sponge.
In an uncycled, planted tank, if the parameters stay good, why would I ever change water at all, regardless of tank size?
Or will the parameters definitely not stay good?


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## Agent13 (Apr 23, 2013)

There is more going on in a tank the ammonia, nitrite and nitrate . If you don't change your water .. Even in a planted tank.. Your TDS will keep getting higher and higher . Pheromones and hormones also are in the water that don't leave till you change the water . Too, eventually your plants will suffer because the trace minerals in the water will get used up and they will suffer nutrient deficiencies . Once your plants start dying then your cycle will crash as you were dependent on plants for your cycle. 


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## David Ash (Jun 11, 2014)

Thanks,

So at least occasional partial water changes seem like a must then- but are 100% changes with a tank scrub ever going to be needed?


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## Briz (Mar 22, 2013)

Not -necessarily-
You may still do it every couple of months just to get a good clean, but generally the purpose of scrubbing objects is to remove algae.


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## Agent13 (Apr 23, 2013)

David Ash said:


> Thanks,
> 
> So at least occasional partial water changes seem like a must then- but are 100% changes with a tank scrub ever going to be needed?



No.. I wouldn't bother with 100% changes or tank scrubbing . 


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## jaysee (Dec 9, 2009)

I had a friend named David Ash with whom I used to work.

I agree, there's no need to scrub.


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## ZZD (Jan 13, 2013)

I have a 10g that is planted pretty heavily. I have a betta, a nerite, 2 panda garras, a handful of ghost shrimp, and a vampire shrimp. My plan was to make it as self sufficient as possible so the betta is in there for looks and the others all have a purpose. The nerite cleans the glass since apparently the pandas don't do windows, the ghost shrimp and occasionally the pandas clean the floor, the vampire shrimp filters the water (as does the filter), and the plants help clean the water as well. I have a wide variety of plants and I do partial water changes, but I can't think of the last time I did a full change. I recently had my nerite go dormant for a month so I reached in and wiped the glass with a sponge I keep for the fish to clean that up till Snail decides to get back to work.

Mostly I have large gravel so I have a turkey baster I use to clean out areas of the gravel when I do a water change or if I notice that for some reason it looks extra dirty, and my tank water is generally clear and I've never had any issues other than one case of popeye in the several years I've had my tank going.


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