Tank Cycling

Hello Venus,

I’m goldfish sitting again. This time, just for 12 days. Since the pump and pond sponge was added last time, it appears that good bacteria were able to grow in the tank!

This is a 5.5 gallon tank with 3 small fantails. Unfortunately, I will not be able to upgrade the tank size as it is not my tank 🙁

Current readings are:
Ammonia=0, Nitrite=0.5, Nitrate=5, pH=7, KH=0.
(No GH reading until new tester arrives).

One of the fantails’ tail frayed before and apparently the tank was salted. When the tail healed, it became black. Current salinity is 0.03ppm. One side of the black tail is longer than the other. I’m not sure if it’s completely healed but I imagine this happened as a result of cycling. The top fin of that fish is also slightly torn. Should we add any treatment to assist in the fin/tail healing? Or is fixing water parameters enough?

Do you think we are in the middle or tail end of cycling this tank? With the current nitrite and nitrate levels, how often should I be doing water changes and how much water should I be changing? Should I dose Prime for the amount of new water added or the entire 5 gallon tank?

Since the KH=0 (very low mineral quality), should I add some backing soda? Our tap water also has close to no minerals and low pH. I have already ordered some small wonder shells to arrive next week. In the meantime, should I add baking soda to raise KH and then add the shells to maintain KH? Or just wait for the shells and rely completely on the shells to raise and maintain KH/GH? If I add baking soda first, how much should I add for 5 gallons?


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  1. emme February 17, 2018 at 6:18 pm

    Hi Brenda,
    Current water parameters are:
    Ammonia=0.3, Nitrite=0.3, Nitrate=5-10, KH=70 and GH=500(!!) GH test arrived…

    I took a break from water changes yesterday which may explain the ammonia.
    Today I resumed 20% water change, remedies and I also cleaned the sponge.

    Is the extremely high GH concerning?? The wondershells have almost melted to half of their original size! I hope it doesn’t keep escalating.

    I purchased some seashells from the pet store. Wondering if I can bury them all under the gravel so the fish can still graze on the rocks above??

  2. Venus February 16, 2018 at 11:33 am

    We rinse the sponges for a few reasons; to keep the sponge free of debris, and able to do its job; filter water, but we also rinse sponges to keep beneficial bacteria from living in them. This encourages them to build their colonies inside the pump, where it’s safe

    I exchange water three times a week, and every time I do a water change, I rinse one sponge in the old tank water I’ve removed with the gravel vacuum. When I say rinse, I dip the sponge in the old tank water, and sqeeze it dry, and then repeat the action. Then I squirt it with a mist of H202, and squeeze again. This assures no bad bacteria is building up in the sponge

    Having one sponge, and with weekly water changes, the sponge would be rinsed once a week. You might lose a bug or two with the rinse, but not enough to disrupt the cycle

    Sponges are for collecting waste, not friendly bugs

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