# Do i need to change water?



## angel4 (Mar 15, 2008)

On 3/8, I bought my 1st tank, a 72G with running Emperor 400, Magnum 350 and 20 cichlids.
Set up the tank with 10G old water, but unfortunately 4 fish died the 1st day.

Turned out my tank had ~1 NH3, 0 Nitrite, ~5 nitrate.
I treated with Prime every other day. Made 10% water change on 3/14, 30% change on 3/21.
The NH3 stayed under 1, nitrite 0, I didn't measure nitrate except for the 1st few days since I still had 0 nitrite.

Finally on 3/29, I had 0 NH3, 0 Nitrite, 5-10 Nitrate and the measurement's stayed the same since then.
I only added ~4G water every week to make up for evaporation, no real water change.

Today 4/18, my nitrate is still just about ~10. All remaining 16 fish are healthy, eat well and swim about freely.
My question is if I need to make regular water change if my nitrate stays low?
Is it strange that it does not go up?
Thanks.


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## akapaul26 (Sep 6, 2007)

Im confused? What did you do to cycle this tank? Water alone from another tank is pretty much useless. If you used an established filter or media from a filter that is fine. As far as water changes I cant clarify unless you give us an exact stock list and if and how the tank was cycled? Water does need to be changed even if your Nitrates are low. Natural minerals etc break down over time and the only way to replenish them is by water changes. I would suggest if your nitrates are low (under 20ppm) after a couple weeks then 25% weekly should be fine. I personally do 50% every week to 10 days. A lot of other people also do 50% weekly which in my opinion is a good guide. Also what kind of tests are you using? Strips are useless glass test tubes are the best and most accurate. Are you using a dechlorinator when adding new water to the tank?


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## angel4 (Mar 15, 2008)

The emperor 400, magnum 350, ~100 lbs of rocks and the fish came with the tank. I had no choice but to keep them. The whole thing was up and running when I bought it. I thought with established filters I was ready to go since day 1.

Like I said, I found that I had ammonia so I had to treat with Prime. I tried to make it as easy as I could for the fish.

Basically, I had to cycle with fish and the tank finished its cycle on 3/29, 3 weeks from 1st set up.
I have a total of 16 cichlids. 4 of them about 4-5in, 4 about 3 in, 8 about 1.5-2 in.


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## akapaul26 (Sep 6, 2007)

Ok it sounds like some of your bacteria was lost during to move of the tank. It sounds like you are completley cycled and good to go now. I would do 25-50% weekly water changes on this tank. The two filters are plenty enough filtration on a 72g so no problems there.


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## angel4 (Mar 15, 2008)

akapaul26 said:


> Natural minerals etc break down over time and the only way to replenish them is by water changes.


Excuse me if this sounds dumb. Why do I need to replenish minerals? Where do they go? I have no plants, what in my tank that needs minerals?


> I would suggest if your nitrates are low (under 20ppm) after a couple weeks then 25% weekly should be fine. I personally do 50% every week to 10 days. A lot of other people also do 50% weekly which in my opinion is a good guide. Also what kind of tests are you using? Strips are useless glass test tubes are the best and most accurate. Are you using a dechlorinator when adding new water to the tank?


I use a master test kit.
I added Prime to the water before I added it to the tank.


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## akapaul26 (Sep 6, 2007)

Here's a couple of articles a friend of mine wrote on another forum I am on. This will give you a better understanding.

Minerals and trace elements in the water are important to the health of your fish, as well keeping the water chemistry stable. Over time they are used up or filtered out. If they are not replaced, the pH of the water can drop. The lack of trace minerals will adversely affect the health of your fish. By doing regular partial water changes is much the same as giving your kids vitamins to keep them strong and healthy.

http://www.aquariumboard.com/forums/articles/4804.htm

http://www.aquariumboard.com/forums/articles/4802.htm


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## angel4 (Mar 15, 2008)

I am sure water change is good advice but can you explain what is happening to my tank:
Finished cycling on 3/29, since then to 4/18, no water change. I made a total of 7 measurements . NH3=0, Nitrite=0 Nitrate <10.

I made 50% water change on 4/19, it took the nitrate down to ~5. Then the Nitrate climbed to ~10 on 4/21 and now at ~25 on 4/25. Ammo and Nitrite still 0.


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## akapaul26 (Sep 6, 2007)

Sounds normal to me. When a tank completes a full cycle you should have a zero reading on nitrites and ammonia. The bacteria you have created will turn ammonia and nitrite into Nitrate. If you are getting readings of Nitrates going from 5 to 25 in 6 days that is pretty normal. Your Nitrates are not harmful to fish unless they are at high concentrations 60ppm or more. High nitrate levels indicate the water is getting foul and needs to have a partial water change done. I dont let my tanks get over 40ppm without a water change usually they don't get to 20ppm. Weekly water changes will help keep Nitrate low.


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## alicem (Jul 26, 2007)

The partial water changes are _good for your fish_ as akapaul26 has indicated.
It also gives you an opportunity to get in there and vac the poo. 
Your fish are probably thriving now and eating better. 
Nitrates are the end product of a functional bacteria colony.
Keep up the partial water changes.
You are doing the right thing for your fish and your fish will repay you with better color, growth and activity.


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## khaki (Jan 12, 2008)

i do a waterchanges every *saturday* and my fish are strong and healthy.


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## alicem (Jul 26, 2007)

By the way, congrats on your first tank. Welcome to the forum. :thumb: 
It's a great hobby and we hope you enjoy it.

One more comment from me on water changes...
If you do at least a 10% weekly water change, it would be beneficial.
That's a little more than 7 gallons for your size tank.
Bump it up to a 20 gallon water change which equals more than 25% .
That would be great and not take that long either.
Once you get in a routine, it will be second nature. You get to interact, in a way, with your fish too.
Also, if you do regular maintenance and something comes up (life happens) you could go over the weekly schedule, your fish would still be ok.
Once life settles down, try to get back on a weekly schedule.


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## angel4 (Mar 15, 2008)

Thanks for all the advice.

I understood that my rising Nitrate now is indicator that my tank has functioning bacteria.
I was just wondering why it was not rising for almost 3 weeks right after it finished cycling?
I have had fish in it the whole time.


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## alicem (Jul 26, 2007)

I still think the fish are thriving more and eating better since the water change and it may be a factor in the rising nitrates.

just my 2 cents,
Alicem


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