Can you ever "over-filter"?

[pass1over]

Currently, my 55gal has a sump with a skimmer in it. All is doing very well.

Im upgrading to a 75gal tank as so0n as I build the stand for it. Going to build a bigger sump and am starting to lean towards adding a refugium as well.

When I got my tank, the guy gave me a large HOB filter with 2 large bio-wheels in it.

Would adding the HOB filter be bad? Would it do anything to really help out?

[jojo22]

I would take out the bio wheels fill that puppy with rock rubble and let the pod production begin!!! Bio wheels tend to become nitrate factories, not really a good thing.

[pass1over]

nice idea
but would I need to do this if im adding a fuge to the sump setup? would the small chamber and rubble help out that much?

[jojo22]

Well your pods wouldn't have to pass thru the pump so more might make the journey and hey going a little over the top never hurt!

[pass1over]

very true ... then anotehr question.
What size overflow box "should" be on a 75gal tank? I built one for my 55gal and was just gonna re-use it.

I thought I read somewhere that the amount of flow an overflow flows depends on the amount of flow from the return pump? There any truth to this? Or maybe I might have to build another one to add to existing?

[jojo22]

Yes that is very true as a 1500 GPH overflow is over kill if you only have a 600 GPH pump now if you switch those numbers around you would probably have some major flooding.

[Iconz]

While I may disagree with joe on the first part of this, there is some truth to it. If you are using an overflow box rated at 1500gph, and your pump is only 600gph, pending on the overflow box design, it should work as long as your box doesn't have problems staying primed/syphon in tact. Keep in mind that your overflow box will only pull as much overflow in as the return pump keeps in the display tank. That being said, the 'ideal' situation is for both of them to be rated the same (overflow = 1500gph / pump = 1500gph). Also keep in mind that you want VERY LOW flow in your fuge, just enough to keep the surface agitated (1-2/hr)...

[pass1over]

Thankyou for your help.
Since I built the overflow myself, it didnt come with a flow rating. Is there any way to figure out how much my overflow box will flow?

[dakar]

What size is the downpipe from the overflow? It's it's 3/4" you can figure roughly 500gph MAX... 1" = 800gph MAX.... heavy imphasis on the MAX as you have to take several things into consideration, like the amount of air that is drawn along for the ride with the water... any bends or other restrictions in the plumbing before hiting your sump... stuff like that...

Or... fill up a bunch of buckets and start pouring, after an hour has passed count how many buckets you were able to get to flow through... J/K!!!! (but would make for an interesting video clip to see someone try it for an hour straight....)

[hummer]

thay would be buzzy thats for sure...lol

[RWalston]

IME you want the pump to have a grater output then the input of the overflow. You can put a ball valve on the pump to limit the water flow. That way you can adjust the flow to match the over flow. This will help eliminate the chance of breaking a siphon because to much air getting into the u tube due to inadequate flow.

[pass1over]

yea, that sounds like a go0d idea to me. Get a pump thats a little to0 big, then plumb a ball valved T off the return line back into the sump to adjust its output?

Ive seen pumps with adjustable flow on them, how reliable are those? Or would it just be better to use the plumbing to regulate it?