Magnum 350 enough power for RUGF?

[MaddMaxx]

Any thoughts on if a Magnum 350 canister could efficently/sufficently "power" a DIY reverse under-gravel filter in a 75g? The tank footprint is 5'x1'.

I'd like to hook the Magnum up to a DIY pvc pipe RUGF to help keep food/crud from building up in the gravel and provide some water flow thru the gravel for beneficial bacteria.

Anyone else try this/similar? Any comments? Suggestions on what size/how much pipe to use? Thanks.

 

[Toby_H]

I doubt the Mag 350 would be nearly enough...

I have a few of them and they have an actual output of around 175 gph... add the additional resistance fo the RUGF and I'm sure it will drop considerably from there... then spread that low flow rate out over 6 sq feet and I doubt you'll have enough flow to even notice...

 

[spiff]

Wouldn't you want to err on the under powered side though anyways? It seems like all you would want is to create a positive pressure under the substate to minimize settling, not necessarily to have sand blowing up or around.

 

[MaddMaxx]

I should add that I plan on having a sump for the majority of the bio-load. I'm really using the Magnum for mechanical filtration and just cause I have it... I thought it might be a good way to keep too much crap-ola from settling on the bottom.

Also (not that it matters) but mathematically speaking, its 5 sqft...

Thanks for the good real-world-check on their outputs tho. Something good to take into consideration.

 

[MaddMaxx]

Wouldn't you want to err on the under powered side though anyways? It seems like all you would want is to create a positive pressure under the substate to minimize settling, not necessarily to have sand blowing up or around.

That's kinda what I thought, I'm not looking to create a lot of flow, just to keep some poo and food outta the substrate... I might try it just to see what happens...

 

[Toby_H]

5 sq ft not 6... I overlooked the detail that your's is not a standard 75 gal

I'm by no means trying to talk you out of it, just trying to theorize what you should anticipate seeing...

If the Mag 350 ends up actually pushing 150 gph through your plates distributed evenly...

That is 30 gph per sq ft... there are 144 sq inches per sq ft... the return lines from most canisters is a little under one square inch...

That comes out to around .25 gph flow per sq inch... that's is REALLY slow...

 

[MaddMaxx]

5 sq ft not 6... I overlooked the detail that your's is not a standard 75 gal

Yeah, just busting yer chops...

Thanks for the detailed calcs tho, thats what I really need to look at. So what if I reduce the effective area by using a DIY RUGF (maybe 2 pvc pipes running the length of the tank)?

Not covering as much gravel, but slightly more force?

 

[Toby_H]

From the perspective of the RUGF...

The PVC pipe approach will work a lot better than using full plates with the limited flow rate you are looking at...

My concern with this though, since it will still be a gentle current, I would only expect it to push the waste an inch or two away from the pipe and let it settle along the front & back glass or between the pipes.

I'm not sure the benefits of the partial coverage will really be all that beneficial...

I'm not much of a fan of RUGFs as I use sand and not gravel and they are much more finicky when using sand...


From the perspective of the Canister Filter...

The PVC attachment will considerably restrict the flow of the filter. Depending on the set up and other filtration this may or may not be an issue...

Personally, I think you could buy a 400 gph powerhead to power the RUGF and this way you are not reducing the effectiveness of the cansiter. But since I brought that up, I should also mention... at that point you may consider using UGF plates and a couple of powerheads to make a full scale RUGF...


I hope I don't sound like I'm criticizing your idea as a whole... I'm just trying to offer a critical view to push the planning stages through, which is what I think you were looking for by bringing your idea to the forum... I'm all about thinking outside the box and to me that's what it looks like you are doing

 

[MaddMaxx]

Thanks for the great feedback. I don't take it as criticism at all, this kind of objective view is exactly what I was looking for.

My hope was to push well-mechanically-filtered water through the gravel to keep it as clean as possible, but looking at the numbers it doesn't sound like the benefit out ways the restriction to flow... construction time and $$ saved, gotta love this forum!