Popular with fish only marine aquariums in particular (although not so much with pure reef enthusiasts), these filters are great biological filters for control of ammonia and nitrites, but poor mechanical filters.
They also can become nitrate factories like canister filters if not maintained properly.
In fact while I have successfully set up canister filters in a way to cut down on nitrate production, this is nearly impossible with a true wet/dry filter.
Generally, the common bio ball wet/dry such as in the picture, which also includes the popular eshopps wet/dry filters, while excellent for control of nitrites and ammonia, are also often VERY problematic for creating sometimes very difficult to control nitrate levels over 40 ppm!
These filters became popular in the 1980s and everyone and their brother made these (often home built), although they are still good filters for certain applications, their popularity is based more on principle and hype than on scientifically proven results.
The problem is this technology, while excellent for waste water treatment is not really all that good for many aquarium applications due to high nitrate production
This high nitrate production is good for a planted freshwater aquarium, but then another negative to these filters emerge, and that is CO2 scrubbing. While it is often possible to have a heavily planted aquarium with say a sponge or FSB filter and need to add little artificial CO2 (such as in the Walstad Method), it is quite rare to maintain such a planted tank without the need to add CO2 via often elaborate CO2 systems.
, in almost every instance where I took on a new client with a wet/dry, in particular with marine or planted freshwater aquariums, in the end I REMOVED/REPLACED with a different system with much better results.
Sometimes all I changed out was the trickle part of the filter (removing the bio balls or similar), as the sump was still useful for live rock, volcanic rock, sponges, SeaChem Matrix, etc.
The principle is that the air holds more oxygen (which is true), thus by passing water thru bio balls partially exposed to the air you can achieve better bio filtration.
What is missed is the fact that an aquarium with proper circulation should have more than adequate dissolved oxygen, not just for the bacteria, but for the fish.
Proof of this is the fact I have achieved better bio filtration with comparable fish loads with live rock (marine only) UNDER water as I have with wet-dry filters bio balls.
I also have achieved comparable results AND BETTER with large sponge filter (sometimes placed in the sump)
I also like to place live rock in the sump too as this prevents in tank nitrifying bacterial die off during power failures.
They are two basic types;
The refiltration flow system allows the owner to adjust the water input depending on the type of fish and plants that are placed in the aquarium. Some types of fish are sensitive to a powerful water flow and can not survive. This is considered the for gentle water flow. The alternate filter inserts that can be purchased separately allows anyone to create the exact type of fish tank they desire. This product also comes with a 2-year warranty on any defects of the filter making it a great water for your next purchase.
Multi-Tank Filtration System - Fish Tank
The Fluval 206 uses a filtration system and a quiet engine to quickly filter your aquarium, and it does this with less maintenance than other tanks on the market today. This filter makes keeping fish easy, and when something is easy, it makes it more enjoyable.
How to create a fish tank filter system without electricity - Quora
Thank you for this great post. I’m planning to get a filler system for my 55 gallons fish tank. Should I get Cascade 700 Canister Filter or Cascade 1000 Canister Filter? Your recommended is really help.
Fish Tank Filters & Filtration Systems - My Pet Store and More