NO3 high after water change

Question
QUESTION: I have a 40Gal tank with 20 fish, Zebras, tetras, 2 red tailed sharks, 1 Peco, Mollies. I have 1 5 inch tall live plant and thin layer of gravel and Whisper Pro 3000 filter. I usd tap water for a 70% change of water yesterday because I had several new fish (5 days old) die after purchase ( Peco and mollies) and the store said my nitrates were over 200. After the water change I bought my own tester and used Amquel + as directed and still my No3 is high, the No2 is now normal after several treatments but is there a better way to treat the NO3? I have had no fish deaths since the change, temp is 77. Also the tap water here was always very acidic and I had to use baking soda to bring it up, now all of a sudden it is too alkaline and I used Tank Buddies PH Correct and that got it normal quite quickly. I feed Wardley flake food and frozen cubed Brine Shrimp 2-3 times a week.

ANSWER: Hello Mac!

First off I have to say...WOW. 200 is crazy.

Now, this can be caused by two things.

1) Tap water. Bring in just normal tap water to be treated. Some cities can have tap water with very high nitrates, some have very low. A cure for this would be more filtration, and more plants.

2) That darn Wardley food. Wardley is widely considered to be one of the worst fish foods out there, and it could easily send all your parameters soaring. I recommend switching to a higher quality food such as Omega One, New Life Spectrum, or ideally Hikari. But really, anything is better than Wardley I find.

The easiest cure would be plants. Stem plants and lots of them. Amazon Sword and Wisteria and very easy to care for, and eat NO3 non-stop. It would be a very good idea to pick out some more plants for your tank. Especially with that pleco. Plecos have a very high bio-load, and is likely a main contributer to your NO3 levels.

Also, what exactly is your pH? The actual number of pH does not matter, unless it is under 5.0 or over 8.5. What matters is stability. Having a super low pH is much better than having a pH that goes up and down all the time. Just leave it as is, the fish you have do not care about pH too much. Like I said, it is all about the stability of the pH, the actual level doesn't matter until you start getting into the more difficult fish.

-Nick

---------- FOLLOW-UP ----------

QUESTION: The Ph is 7.0. I will definately take your suggestions. I had the water tested at House of Tropicals yesterday because some say not to trust the test strips and their liquid test showed very high (orange) NO3 and they suggested using Stress Zyme to put "good" bacteria back into tank. I only got the Plecos because the Chinese Algae eaters kept dying, I have one Pleco left and I will leave it at that. So far no more deaths and will continue testing and treating if needed and get some more plants. Do you think feeding Frozen cubes of Brine Shrimp would be a problem? I have done so maybe twice a week?

Answer
No, the brine shrimp isn't the problem. Brine is a very good idea, just make sure not too much is wasted.

7.0 is the pH before you do anything to it? Leave it at that, it is perfect, no need to change it. Even if your pH was 6.0 it is better if it were stable than if it were ideal.

There is no good bacteria that will get rid of NO3. The good bacteria will turn other, more harmful toxins into NO3, but the only way to get rid of NO3 is in water changes and plants.

And yes, the test strips are usually very unaccuarate. I perfer the API drop tests.