Nitrate level problems

Question
I have a 6-gal freshwater tank with a biological filter, 2 goldfish (~2 in. each), and an ottocinclus.  The tank is 6 months old and was doing fine till a couple days ago.  I don't know about the PH or nitrite levels, but the Ammonia level is 0 ppm, and the nitrate kit says the nitrates are between 40 and 80 ppm (down considerably from a couple days ago).  I had been doing 10% water changes every 1-1.5 weeks depending on the nitrate and ammonia levels which had been hovering about 5-10 ppm for nitrates and 0 ppm for ammonia.  I was gone for 1.5 weeks out of state, came back and the nitrates were at the top of the scale (~160 ppm).  I can't figure out what happened while I was gone.  

I did one 30% water change, then I've been doing 10% water changes every day and adding ProQuatics bacteria starter to get it down to an acceptable level. I have a plastic bucket that I put water in and let it sit 24 hours before doing a water change.  

The fish don't seem to be gasping or acting any differently then they have for months.  Any ideas on how to properly get the tank back in balance and keep the boys happy?

Martin

Answer
Hi Martin;

They just need a bigger tank. Goldfish are deep-bodied messy fish that require lots of room to thrive and grow. They get to be 6 to 8 inches long and live to be more than 10 years old if allowed the space.

I would get a 20 gallon for the two goldfish and otocinclus. This gives them room to grow and plenty of room to romp! They may need more space later but in the meantime they can have fun.

Followups welcome

At Your Service;
Chris Robbins

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