jar05g

Hello all. So I've had my 30 gallon up and running for about 3 months now. It's finished the cycle. ammonia and Nitrites are all 0, Nitrates are about 10-15. pH is 7.2. I currently have 3 Blackskirts, 5 Neon Tets, 5 Serps, 1 Cory, 4 Black Neon Tets, 6 Pristella Tets, and 4 Magnificent Rasboras. Water temp. stays constant 76-78 degrees. I have a HOB Emperor 280 filter. I also have two different sources of aeration...one being from a volcano, and the other is a 10'' air strip that I have under the gravel. I have been doing weekly 10% water changes, but I haven't seen my Nitrates come down any. My question is...would doing 25-30% water changes weekly be too much? Would it send my tank back into a mini-cycle? I'm also dosing my tank with Tetra Algae Control to get rid of the left over diatoms and some of the green algae that I'm starting to see. Any suggestions?

Tavel

Your nitrates aren't going down because you have a really heavy tank load. I added it up and you have 50 inches of fish in a tank that should only have 30 to 36 inches of fish.

Besides, 15ppm isn't even that high. All the literature suggests that 40ppm is still "safe", you're not anywhere near that.

jar05g

Ok...but would doing that big of a water change once a week be too much or what?

Tavel

haha, i forgot to answer your question. I don't think so, as long as your filter has enough bio-filtration. I wouldn't recommend it if you had a whisper filter or something, haha.

I change 20% every week in all of my tanks, I've never really had a problem.

Peterpiper

Jar05g,
Water changes will not damage the bacteria in your tank.
The stocking level will affect your water quality.
The results of you testing will govern what needs to be done in regards to water changes. Readings of Ammonia or Nitrites will require you to do larger water changes and address the issue of why you have the readings.
Nitrates. As every system is different, nitrate build up will vary from one system to the next. Some things that affect Nitrates include, Filtration systems, Algae's, Plant's, Feeding, Volume and Stocking levels. A large tank, lightly stocked, running a good filter with plants and Algae's will have a lower Nitrate build up than a tank that is heavily stocked, has no plants or Algae's.
If you find that your Nitrate levels are slowly going up when you do your weekly tests, then you will need to increase the % of your water change. Good reason to have low stocking levels, large volume, good filtration and some nice Plants.