Tank smells

Question
-------------------------
Followup To
Question -
4 months ago we switched from a 10 gallon tank to a 30 gallon.  About 4 days ago, the tank began smelling very acidic.  I did a 50% water change 1 week ago because the amonia levels were high.  I checked the levels yesterday and all levels were fine.  Due to the smell, however, I changed about 70% of the water (I kept flushing and adding as I removed).  Again, the levels are all fine, but the tank still smells acidic.  I lost a small shark 2 days ago.  What are we doing wrong?  What should we do?
Answer -
Hi Becky;

How many fish do you have?
How big and what kind are they?
What type of filter system?
How much and how often do you feed the fish?
How long does it take for the fish to eat all the food you put in the tank?

Let me know as soon as you can......


Thank you for your reply.  We have 1 four-inch algae eater, 1 three or four inch silver dollar, 1 two-inch shark, and 6 one-inch mollies.  We have a charcoal filter that hangs over the back of the tank for a 30-60 gallon tank (our tank is 30 gallon).  We feed one or two times a day and they gobble it down in about one or two minutes and act like they're still starving.  We vary their food by alternating feeding them tropical fish flakes, dried worms, and algae eater discs.

Answer
Hi Becky;

Elevated ammonia always relates to excess waste in the tank. The gravel probably needs vacuuming. Vac the gravel while removing 25% of the water twice a week for a couple of weeks. If you get a lot of crud out of the gravel when you vacuum it, cut back on food too. I am a member of the "overfeeding club" myself. It is pretty common. Even if the fish seem to eat all of the food really fast, the algae wafers or worms might just be too much for the filter system. Feed the fish greens too. Chopped spinach and cooked and cooled green peas are good. It will help them feel more full without the proteins and fats of regular food that can pollute the tank.

Followups welcome.

At Your Service;
Chris Robbins