why do we do water changes in planted tanks?

[tbonem91]

I know, I know it sounds silly... but I got to thinking the other day...

Isnt the main reason for water changes to remove NO3 and gravel vac at the same time?

Well, in a planted tank, we are adding NO3 and aren't gravel vaccing (for those with a lot of ground cover anyway)... then what is the purpose to changing water in a tank like that? For those of us that dose micros and macros and dont need to vacuum the gravel, the only purpose I see to changing the water is to have a bucket of tank water to rinse out the filter media periodically.

Am I missing something? 8O

 

[Purrbox]

The purpose it to remove TDS (Total Dissolved Solids) and replenish the trace nutrients that your ferts assume you're already getting with your tap water. In a high light tank it also serves the purpose of resetting your fert levels so that there is less chance of developing an imbalance.

 

[cbk.o4]

the only reason i really did a pwc and vac today was cuz im going to start dosing my dry ferts today wanted to start with a clean slate, and i had a bunch of plant debris from the trim i did this morning.

 

[tbonem91]

The purpose it to remove TDS (Total Dissolved Solids) and replenish the trace nutrients that your ferts assume you're already getting with your tap water. In a high light tank it also serves the purpose of resetting your fert levels so that there is less chance of developing an imbalance.

oh. makes sense

 

[current516]

Took to long to post. irrelevant now.

----
hmmm... good question.

I don't know the answer but someone must.

On top of that many of the aquarium horror stories I read begin with, "after I did my PWC"

 

[rich311k]

I do it to reset my ferts levels and to to refresh all the traces that are found in water. I would do 50% weekly with any tank wether planted or not. I think those post water change disaster occur because either it was to long in coming and the fish could not adjust to the cleaner water or not enough attention was paid to KH and temp in the replacement water.

I figure fish live in rivers and creeks in the wild they would get 100% water changes all the time. I know mine look much better and are more active after a water change. I would do more of them if I had the time.

 

[TwoHobbies]

It's common with people on this site, but I bet for everyone who changes water weekly there is a 100 who don't.

Before I came here.... I didn't know anyone who did PWC, but...

Those same people come to my house and can't believe how good my tank looks.

 

[Jchillin]

A good rule of thumb (which is what I use) is the water change schedule is totally dependent on what level of planting you have.

I change my water bi-weekly. That is because it is low-light but heavily planted and carpeted. I know I will have to replace the macros that just went down the drain but I can't imagine putting my fish through living with a lot of TDS's.

For those of us with canisters, particulate matter can build up in the hoses and will eventually come out into the tank...we don't want that in the tank.

 

[fish_4_all]

The only thing I know is when I got to a lake or river and I find thjose water areas that don't get fresh water from whatever source that feed the lake or river, plants don't grow in them very long. I have also seem many fish in these "stagnant" areas but very few alive.

I will admit, when I had my 55 gallon not 11 years ago I didn't do any water changes for months, ok, 2 years. I had a tank that was absolutely beautiful. Clear water, no plants, about 30 inches of fish and no troubles. Shortly after that time frame, major crash, all fish died and tank went sour, litterally. Stunk like a stagnant pond full of skunk weed and deed fish. This happened in less than 2 days time.

Long story short, nature replenishes everything at least once a year. I know it sounds like a big jump to do it once a week but we spend a lot more time looking at our fish than it takes to do a PWC so why not? Even if it is only once a month as long as it is regular and thorough.

Case in point, even my local fish hatcheries have to get down and scrub the runways absolutely clean even though the water the fish are in is fast flowing and exchanged every 10 minutes. It was a hard lesson learned by one local hatchery when they didn't do this and lost 60% of the salmon and steelhead fry they were supposed to raise. Disease was known, cause, buildup of bacterial cultures under the moss that grows on the walls. If a hatchery can get those kinds of diseases and the water is changed out 144 times a day imagine what can happen in a 10 gallon tank that isn't changed but once a year or less.

 

[crazyred]

Basically comes down to 3 words......flush the toilet. I'm sure even with plants, fish don't appreciate swimming around in their waste all that much, and that stuff doesn't go anywhere.

 

[malkore]

and TDS include Dissolved organic compounds (DOC's) which plants can't utilize.

Also keep in mind that in the wild, the water is constantly being renewed from rain, snow melting...the natural flow of things.
We need w/c to mimic this behavior.

There are ways to do heavily planted tanks with hardly any fish, where you only top off with lightly reconstituted RO water (to prevent Kh/Gh buildup), and only do a water change a couple times a year.

But its a pretty big undertaking, and I know I wouldn't have the patience to do something like that.