Filtration in Large Goldfish Tank

[Terraphyte Tank Guy]

Hello...

I set up a larger Goldfish tank some weeks ago and purposely left out the filter, deciding instead to remove and replace two thirds of the tank water every week. I did this for several weeks and noticed even though the water chemistry was very good with no traces of ammonia or nitrite and nitrates in the 20 ppm range, the water wasn't as clear as the same tanks with a couple of dual sponge filters going in them. This week, I put in two dual sponge filters in that tank and changed out just half the tank water. Within a couple of hours, the tank water was crystal clear. Interesting that the larger water changes didn't keep the water as clear as using a couple of simple filters.

TTG

 

[Backfromthedead]

Sponge filters are a thoroughly tested and proven piece of equipment. Nothing better for neutralizing small particles in the water column imo. How large is the tank and the sponges?

 

[Terraphyte Tank Guy]

Sponge filters are a thoroughly tested and proven piece of equipment. Nothing better for neutralizing small particles in the water column imo. How large is the tank and the sponges?

Hello Back...

This particular tank is 55 gallons and I'm using a couple of dual sponge filters. The sponges each roughly 4 inches by 1 inch. The tank has 12 Comets about 2 to 3 inches. I'm removing and replacing half the water weekly. Water typically tests out at zero for ammonia and nitrite and nitrate around 20 ppm.

TTG

 

[Rocksor]

You need larger sponges if it can't keep that 55g tank clear of particles.

 

[Terraphyte Tank Guy]

You need larger sponges if it can't keep that 55g tank clear of particles.

Hello Rock...

Two dual sponge filters seem to be doing the job better than the larger, weekly water changes.

TTG

 

[TwoHedWlf]

Interesting that the larger water changes didn't keep the water as clear as using a couple of simple filters.

TTG

Not surprised, they're mechanical filters, not just biological.

 

[duanes]

Water changes are not really done to produce clear water.
They are done to remove dissolved, invisible organic compounds such as nitrate that ruin water quality, and cannot be filtered out. They can help remove colors that are in solution, and if you vacuum at the same time, removing nitrate precursors, and junk that can hinder clarity.
Water changes are also, for replacing certain buffers and essential nutrients like calcium.
The only real purpose of mechanical filtration is polishing, and producing clear water, free of particulate .
Biological filtration is almost soley for removing ammonia and nitrite.