so i believe i may well have built myself one of the best filtration devices i have ever owned for a fish tank. the entire construction took 30 minutes at most (mostly nipping away at lighting diffuser)
i started off with a storeage bin from walmart, one of the smaller sized containers with the attatched lids. i then cut a hole in the bottom of it with my pocket knife and stuck one of my spare 1" bulkheads into it along with a short stick of 1" pvc tubing to the return. i then laid 2 sticks of pvc along the length of the bottom of the container purely to act as a spacer. i then put a piece of lighting grid cut to fit the inside ontop of this spacer. then there is a 6 pound bag of lava rock for a propane grill spread ontop of the light diffuser. this is several inches thick in the layer, this is your bio filtration. there is then another layer of the light diffuser. and at walmart in the crafts department i bought 2 yards of 100% polyester fleece type fabric, loose woven, i assume you would say use it to insulate a jacket. well it works great for a fish tank filter too. at 2 dollars a SQUARE YARD, its extremly inexpensive compared to buying filter cartridges. anyways thats the entireity of the filter components with the exception of the pump, which is hooked up to half inch tubing returns to top of the unit, which is then plumbed into a 3 way spray bar of my own design. Paul's filtration devices was 100% my inspiration for this project, i just didnt want to use plastic bottles so i used a plastic storage bin instead. also its very light weight since it doesnt actually hold more than about an half inch of water in the bottom of the container. i have not had true clarity in that over stocked koi tank in over a year due to the bioload in that tank (its NOT my tank, i wouldnt keep koi in a fish tank, its my sisters and ive been asked to care for it in her absense at college) untill now. this is great!!!
anyways, this whole thing cost me about 20 dollars in materials (less the pump, a freebie i found out in my shed unopened brand new in the box from god knows when), most all of which i already had.
100% success in this project.
has been up and running a couple weeks now with phenominal results.
ill see about drawing a schematic of it, or take some better pics of the internals next time i clean it. i was waiting on posting this to see if it would actually work well or not, and it works fabulously! i dont care how many boxes of fluval ceramic rings u buy, a 6 dollar bag of lava rocks has more surface area for bacteria to grow on than several boxes (at 20 bucks each!) of those fluval ceramic rings. who said this was an expensive hobby???
(im going to shorten that return tube one of these days, it doesnt need to go that low into the tank, it just needs to clear the hood and allow the water to fall back into the tank without making a mess.)
