Fluidized bed in a wet dry filter ?

[B_IN_SD]

I also made this. I saw cut a strip of 1/2'' acrylic, then I turned it on the lathe polished it to 2500 grit and then flame polished it. Yeah I have too much time lol
I will cut this piece in 1/2'' segments and use the parts to space the diffuser plate off the bottom.

 

[B_IN_SD]

The diffuser plate is the square part under the top plate, also what the top plate looked like when I started. I am still working on a hole size and shape that I like for the difuser plate when I finish it I will post a pic. The weld-on cement and applicator should be here friday.

 

[B_IN_SD]

Hi

My two cents worth; From your pictures your filter fulfils both these criteria as skimmers also often have similar constraints. To stabilize media height just use a slightly larger grain size and up the pump size slightly to suit. The best pumps for fbf have a higher maximal water head than normal powerheads which makes restarting easier. The eheim range of pumps is a good (but expensive) example. Pump the water through a couple of inches of coarse rounded gravel in the bottom of the fbf (gravel shouldn´t move) as well to ease startup problems. Don´t forget to occasionally clean the gravel though.

j<><

Will pea gravel or small lava rock work for the bottom of the fbf ? A eheim pump would be better suited for this app. What flow rate would you suggest ?

 

[B_IN_SD]

bump

 

[justin guest]

Will pea gravel or small lava rock work for the bottom of the fbf ? A eheim pump would be better suited for this app. What flow rate would you suggest ?

I´d suggest the gravel to be around 12-15mm diameter. Because of the irregular shape of the single stones lava will clog too quickly and distribute the water unevenly into the sand bed.

The flow rate for your diameter is of course dependent on the type of sand but around 1200-1500lph at zero head should be ok. You will need a regulation valve on the pump in any case. The optimal active bed height is 125 -175% of the bed height when the pump is turned off. When possible you should tune the pump to an active bed height of 150%.

j<><

 

[B_IN_SD]

Thanks for your help hopefully I will have it going by this weekend.

 

[justin guest]

Good luck

j<><

 

[B_IN_SD]

I just ordered a 3/4" od 15" long section of clear acrylic tube that will be the water inlet and run from the difuser plate at the bottom to 2" above the top of the fbf it should be here monday. So having the fbf running by this weekend is out the window but I realy did not want white pvc tube in the center.

 

[B_IN_SD]

Got the difuser plate done this morning, it turned out pretty good if I do say so ! I am still waiting on the weld-on cement and the inlet tube.

 

[justin guest]

looks good
j<><