30 Gallon Tank Water Parameters Help!


Water Parameter & Filter Help

Hello everyone..

Well I have done about a 15%-20% water change yesterday and I went to check the parameters and had high ammonia and nitrites. Why are they so high after a water change the day before?

I do add Tetra Aqua "Aqua Safe" Water conditioner before I put the water in.

PH Low: 7.6
PH High: 7.8
Ammonia: 2.0ppm
Nitrite: 1.0-2.0 ppm
Nitrates: 5.0ppm

also to be sure I tested the nitrite and ammonia multiple times and got the same readings. Should I do another water change or what else will help get them down?

Also another question..
I have HOB filter and was wondering when I change the filter cartridge, do I just take the old one out and put the new one in? or what do I do for that?

Thanks for all the help on this lovely forum


Do you have any fish in the aquarium? If you don't, it should be fine, as the tank is cycling. Are you using the freshwater master test kit? If you're using test strips, they are known for being inaccurate. If you have fish in the aquarium, I would do another water change to bring them down. When changing the filter cartridge you have to be careful, because it contains most of the beneficial bacteria that keep your cycle going. If your filter cartridge is dying, make sure to add another so that it colonizes before you have to throw the other out.


Have you tested your tap water for ammonia? Mine has 1ppm and until I tested I just couldn't figure out why water changes never made a difference.

A 15-20% isn't very large if your goal is to reduce the ammonia. You'd need to do a 50% water change to reduce your ammonia from 2ppm to 1ppm (assuming there's no ammonia in your tap water). What is your ammonia source for your cycle?

Keep rinsing and reusing the filtration media you have now until it falls apart. If it's the kind with carbon inside, slit it open and remove the carbon when it's time to change it. It's personal choice about using carbon so you can either go without it or add some new carbon before putting it back in the filter.

  • Thread Starter


I have already let my tank cycle and has been up and running for around 2 months now. I do have fish in there. 2 DG's, 3 Guppies, 4 danios & 2 snails. they have all been in there for awhile and have been looking good going through the harmful waters that just happened. I just did another WC (50% this time). let me go check my tap for ammonia.
Alright, the ammonia for my tap is 1.0ppm too.


Hello Exiled,

I recommend adding Prime or Amquel + in addition to your water changes. These will detox the ammonia for 24 hours until it's time for the next water change. Check your readings 24 hours after adding the Prime or Amquel + to get an accurate reading.

With 1.0 in your tap, once you regain your cycle, the cycle alone should be enough to process that amount in 24 hours and not do harm to your fish.

Tetra Aqua Safe removes chlorine and chloramines and does nothing for ammonia.

Best of luck and keep us posted.

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