Hi Guys and Gals, After a long deliberation on filters design and looking at pricing, especially importing the fancy ones and HOB and canisters, I have built 2 prototype for testing purpose and there after build to order. I started this design in the early 1990's with my 400L as I could not afford a new filter. It has proven itself over the years as an effective filter. Intake to the filter is in the lower corner as this is where the most fish waste occurs where as many filter either have their intake mid-water or skim off the top. Maintenance is basic, remove filter media, either clean in RO water and insert again or replace with new. These bio filters will be built to your tank requirements, all is required is the inside width and overall depth of your tank, 2 versions will be available, first being complete box and second silicone to the side of tank, the space required is about 10% of your viewing panel. Each filter will comprise of 4 chambers, first for filter floss, second for filter sponge, third for ceramic rings, activated carbon and any other media choice, fourth chamber will house your return pump and heater. With this design, which is black, one does not see any of your equipment and this is concealed in the internal bio filter. I have run this on a 3ft and 4ft and have not done any water changes in the past 6 months plus, not changed any filter media and the water parameters are all perfect, the second advantage is in the event of power failure, there is no need to worry about pumps running dry, sumps overflowing...... Please note this will be a complete filter assembly excluding any filter media,return pumps or media. Shipping will be for buyers account and deliver will be about 1-2 weeks from date of confirmation. Custom size sump filters can also be made according to your requirements.