# Skippy/Wendy Filter > Can you explain the size to gallons ratio?



## YMS_1975

I _was_ running an EHEIM Professional 3 - 1200XL - 2080 canister filter prior to this post, however because it was sitting flush (levelled) with my poly stock tank (on the ground level), I was constantly running into problems with the water flow. That's when I learned it's intended use was to be under an elevated aquarium/habitat. Lesson learned. 

I've been researching this online and I belong to another community (geared towards turtle owners), and the subect of the "Wendy" or "Skippy" filter came up.

I'm sure you fine folks understand the concept of what that is, but if there's anybody out there reading this, who is as ignorant to the matter as I was...it's basically a make-shift filter, run by a pond pump into your own make-shift canister.

Here's where things get kinda confusing for me. My previous filter was rated for up to 320 gallons; at least that's what it said on the box. Despite not being a trusting fella, I decided I'd trust EHEIM on this one. Having said that, the canister itself held 6.6 gallons. The motor/propellor pumped out 450 gph. I never measured this, but I'll trust them on that too.

SO.... knowing what we know about my previous canister filter held 6.6 gallons, pumped out 450 gph, and was rated for up to 320 gallons.....how powerful a pond pump do you think I would need for my skippy/wendy filter?

Keep in mind that this time around, I want three times the filtration than what I had before. So, instead of a canister filter that's rated for 300 gallons (I'm rounding down from 320), I'd like to make a skippy/wendy filter that's rated for up to 900 gallons.

1) Is it the canister size that determines the gallons ratings?
2) Is it the GPH that the pump pushes out/pulls in that determines the gallons ratings?
3) Is it simply a matter of me multiplying the numbers by 3 to get my answer, or is there a more accurate method of doing this???

Sorry for the long post, but this is a bit tricky and my poor turtles have no filtration right now (I've been doing weekly changes in the absence of their filter), so I want to get this right.


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## Ryan.Wilton

So from what my math tells me about the filter. .1 gallons needs 68.2gph, (450/6.6). If the effective rate of 0.1gallon is 68.2gph, then the statement for the filter capacity could be (350/6.6) 48.5gallons per 0.1 gallons of water held in the unit.

Therefore, 6.6gallons=320gallons, so logically 900gallons should = to 18.5625 gallons, or 19 gallons (for the canister)

So, if the statements above are true, then 68.2gph x 18.5625g give us your flow rate that you wish for the pond pump, 1265.9625 or 1266gph. You need a pretty powerful pump in order to do this wish. You'd be basically making a sump filter.


So in closing, you pretty much need a pond pump that flows 1300gph, combined with a minimum 19gallon cylindrical water vessel.

Hope this helps


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## pyrrolin

capacity for tank size is a combo of media volume and gph.

If its a turtle tank, I assume its more water cleaning than bio load. I would recommend high gph pump and not worry to much about the size, but this depends on the bio load.

I guess basically the media volume is for the bio load and the gph is more for the size of the tank.

Not sure if I actually helped any


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## Ryan.Wilton

If turtles, I agree with Pyr. It's more about the water, so changing it often is very useful (believe me I have 3 turtles in a 55gallon... That water stinks weekly if I don't do a 50% w/c at the very least, I usually do 75%)


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## YMS_1975

*...*



Ryan.Wilton said:


> So from what my math tells me about the filter. .1 gallons needs 68.2gph, (450/6.6). If the effective rate of 0.1gallon is 68.2gph, then the statement for the filter capacity could be (350/6.6) 48.5gallons per 0.1 gallons of water held in the unit.
> 
> Therefore, 6.6gallons=320gallons, so logically 900gallons should = to 18.5625 gallons, or 19 gallons (for the canister)
> 
> So, if the statements above are true, then 68.2gph x 18.5625g give us your flow rate that you wish for the pond pump, 1265.9625 or 1266gph. You need a pretty powerful pump in order to do this wish. You'd be basically making a sump filter.
> 
> So in closing, you pretty much need a pond pump that flows 1300gph, combined with a minimum 19gallon cylindrical water vessel.
> 
> Hope this helps


Yeah, this is what my math came out to as well 
So now, all that's left is getting a good pond pump.

I'm leaning towards Oase. I heard they make a great pump. Any thoughts on Oase?


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## Ryan.Wilton

For my pond I use a Tetra Pond filter (I think it's tetra brand.) and a laguna powerhead for the internal pond flow. I've always had luck with lagunas, but you will have to find a pump that'll fit your needs. You may want to actually invest in an large capacity one, similar to what people use on their larger reefs. (go to home depot lol)

Oh and just a though for this, why don't you set up the sump instead. If you use say a trash can, sealing it is going to be a huge issue. Especially when you need to open it back up to clean/change the media.


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## YMS_1975

Ryan.Wilton said:


> For my pond I use a Tetra Pond filter (I think it's tetra brand.) and a laguna powerhead for the internal pond flow. I've always had luck with lagunas, but you will have to find a pump that'll fit your needs. You may want to actually invest in an large capacity one, similar to what people use on their larger reefs. (go to home depot lol)
> 
> Oh and just a though for this, why don't you set up the sump instead. If you use say a trash can, sealing it is going to be a huge issue. Especially when you need to open it back up to clean/change the media.


Not sure I understand the need for _sealing_ the lid. The way I see it, I'd have the pond pump in the habitat. The tubing (running from the pond pump) would be connected to PVC piping which runs into said trash can. But that PVC piping doesn't necessarily have to gain access from the top lid. It could be running into the trash can from _below_ the lid.

Opening & closing it (for the sole purpose of media changes), would simply be a matter of using the lid as one normally does (on and off). I'd apply either some sort of a silicone or adhesive (which was outlined in the video I saw on Youtube) to ensure no leaks occur within the access hole (which I'll be creating _below_ the lid) for the PVC piping to get in there, when gaining access to the trash can.

Hope that made sense.


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## Ryan.Wilton

I suppose, I figured he wanted to make a mock canister. I guess if the PVC was attached through the side, and below the lid line then I guess. I was just thinking if the water was being evacuate through the top, if the edges weren't sealed it had an overflow risk lol


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## YMS_1975

*...*

That's true; something I've considered as well but I plan on giving the output a significant diameter output size of 3" or possibly even 4".

So I think I should be ok. *Fingers Crossed*


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## Ryan.Wilton

Hope so for your houses sake lol. Other wise a little DIY, could turn into a lot


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## TorontoBoy

*Wendy Filter References*

For my turtle, who is very dirty, I am planning to build a Wendy filter.

For the sake of others wanting to know about the Wendy filter, here is the reference back to Wendy and a schematic of her filter design on p3. You can only see the photos diagram if you join their forum.

In general the Wendy filter can be as large or as small as you wish. There is a prefilter and a pump that sits in the water. Water is pumped out of the tank to bottom of a container, where the water rises. A second pipe is drilled into the container below the top line of the container, and flows water back into your tank. In the container she usually only puts large rocks and then some lava rocks. I'll probably put traditional biomedia ceramic cylinders and pot scrubbers.

[I have a diagram of the Wendy filter but cannot figure out how to post it. You need to log into another forum to see the diagram, so a URL will not work.]

For pumps she uses anything from a pond pump to an 80gph water fountain pump. For containers she uses anything from a large rubbermaid container to a candy jar.

The issue I have is that for the Wendy filter to work the outflow from the container has to be above the waterline of your tank. The top edge of my turtle tank is high, so I would need to elevate the container so that the outflow will clear the top edge of my tank, which is at 4'.


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## pyrrolin

so that is a Wendy filter, thanks for the link, been curious about it


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## Ryan.Wilton

Ya TorontoBoy, When I was reading that post, I had been considering the same thing. However, if you were to adjust the intake to use gravity (via a shut-off valve) you could easily set it up with the pump on the return and solve that issue.

I might build one for my Turtles... the stupid Rena XP4 isn't working right (maybe because it has the top of a Rena XP1 cuz the 4 broke lol)


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## TorontoBoy

Ryan.Wilton said:


> Ya TorontoBoy, When I was reading that post, I had been considering the same thing. However, if you were to adjust the intake to use gravity (via a shut-off valve) you could easily set it up with the pump on the return and solve that issue.
> 
> I might build one for my Turtles... the stupid Rena XP4 isn't working right (maybe because it has the top of a Rena XP1 cuz the 4 broke lol)


Yes, I could restrict input with a shut-off valve as well as put a pump on the return, but if the container outflow was below the aquarium water line I would worry about the container overflowing if that pump failed. Wendy's containers do not have water tight lids, unlike canisters, so it is difficult to overflow. If I flooded our living room there would be hell to pay, and our turtle, and probably I, would be looking for a new home.

I was in Aquapets (Steeles/Kennedy area) this week and at the front of the store I think they have this type of setup for their 2 koi tanks. They have a big ass sponge prefilter, then a large pump that flows the water up to a huge black rectangular covered container that looks like the size and shape of a tool box off a pickup truck! Water then flows down, using gravity back to the koi tank. They have one for each tank, and the water and fish looked really clean.


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## Ryan.Wilton

Yeah, this is the main idea for a sump filter. Like I said before, just go with the sump design and all should work out well. Beyond which, if you were to install a secondary overflow pipe, above the return and have it go through the floor/wall to a drain pipe, then you'd have no worries


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