If I put the intake for a filter in the tube on an undergravel that is ABOVE the water surface will gravity keep enough water in the tube to supply the filter? Letting use the undergravel as prefilter and not disturbing the powerheads. 
Will this work?
- Thread starter BumBumBee
- Start date
hmmm interesting idea!! my uneducated guess would be that it might work fine.........sounds like it wouldn't hurt anything to give it a try!!
I'm going to try it. I am pretty sure it will work. It's a 45 gallon tank and I think the water wieghs like 400-500lbs so I think that will be a lot of presure pushing water back in.
Depending on the particular HOB being used and the tightness of the coupling between the UG riser of the HOB intake, it should work.
However, I question the reasoning behind the effort to have it work. In general, having two filters in series (that is, one - the UG - feeding the other -the HOB) driven by a single motor is less effective than having the same two filters in parallel (each filter operating independently). The sum of the two is almost certain in practice be less than the sum of the parts, the total may in fact be less than either of the components individually.
Is there some over-riding reason for this coupling of two filters? If not, I would not do it myself.
However, I question the reasoning behind the effort to have it work. In general, having two filters in series (that is, one - the UG - feeding the other -the HOB) driven by a single motor is less effective than having the same two filters in parallel (each filter operating independently). The sum of the two is almost certain in practice be less than the sum of the parts, the total may in fact be less than either of the components individually.
Is there some over-riding reason for this coupling of two filters? If not, I would not do it myself.
I'm using the canister for chemical and water movement mostly. The UGF will have enough biological filtration along with the canister. I just don't want to suck up a bunch of fish food at every feeding and have to clean the canister. The UGF keeps the water clear all by itself already. Other people are using sponges and stuff to pre-filter, I just thought it would be easy to use the UGF.
A sponge prefilter is much easier to just take out and rinse and then being sure all of thegunk is out of the tank. The UGF will prefilter for the canister, but then the gunk is still in the tank rotting away.
Yeah, I agree... you'd be maximizing the worst aspect of a conventional UGF: the tendency for it to pull in crud, where it is broken down and contributes the pollution in the tank.
No offense intended, but that's one of the more inappropriate uses of a UGF that I could think of...
Jim
No offense intended, but that's one of the more inappropriate uses of a UGF that I could think of...
Jim
FINE!
Do you think it would be better to reverse the flow in the undergravel? The hagen 802's will flow backwards. I think I would rather figure out how to hook them up to push water forward down the UGF tubes since there is a major differance in the flow rate forward and backward.
Do you think it would be better to reverse the flow in the undergravel? The hagen 802's will flow backwards. I think I would rather figure out how to hook them up to push water forward down the UGF tubes since there is a major differance in the flow rate forward and backward.
Yup! I think it's always preferable to run UGFs in reverse mode. That way they don't become compacted with poop and stuff. If you add prefilter sponges over the powerhead intakes, you not only get some extra mechanical filtration, but you also keep crud out from under the UGF plates.
Jim
Jim