Splitting a canister filter three ways

[SamH]

Hello all,

Looking at getting three tanks running off a single canister filter. Not really worth buying three separate filters for three 54L tanks, but Fordayzbro came up with the brilliant idea of splitting the flow three ways. Here's a diagram to show the idea visually.

1. Is this possible? Any issues you can see?

2. What can I use to split the flow?

Thanks!

-Sam

[phoenix44]

Well your tubes will have to be exactly the same length, width and must never get blocked.

Water will take the easiest path.

then you need to make sure that water in = water out in all of the tanks. That's the hard part.

[fordayzbro]

Sump it!

Must be a few examples around on the web......

That way you can get a really grunty pump that would give loads of flow.

A cannister filter would need to be hell powerful to circulate through 3 split pipes.

It can be done

[livingart]

drill tanks plumb together

water in 1 end, out the other

[SamH]

Hmm, I'm not good with overflows and drilling is risky yeah? It's only 6mm glass though so I guess it'd be easier.

[kiwiplymouth]

Water will always take the path of least resistance so it will be a nightmare to get this to work efficiently in each tank.

They are only small tanks, I would just use a sponge filter in each.

[spoon]

what could possibly happen is you end up sucking more water out of one tank and pushing more into the the others causing an overflow drilling glass is really easy just buy some diamond holes saws of TM or ebay and practise on a scrap piece of glass

[SamH]

I might just stick with my internals, I just don't like having heaps of gear in the tank. I wanted them all the same but one's slightly smaller than the rest, I'll live.

Just thought this would be a cool concept, guess it's just not practical.

Given the sump idea some more thought, it could be good. 10mm drill bit only $7 off TM, but would I need 3x 10mm elbows then?

[ryanjury]

drill tanks plumb together

water in 1 end, out the other

This is the best way to do it... You could even run siphon based overflows between each tank, I have done this and it worked but has its risks.

[spoon]

you would get much flow out off a 10 mm hole and it may be hard to find 10mm elbows id suggest using a 22mm mm hole saw and using hansen 15mm bulkhead fittings then go with flexible tube and irrigation fittings for cheapness

[SamH]

So a 22mm hole would be suitable for a 15mm bulkhead then?

And the best way to plumb them all together?

[spoon]

yep for a hansen one , if the tanks are stacked on top of each other you could over flow the top one into the next one and the bottom one into the sump or plumb all of them separatly into the sump

or if the tanks are all the the same level you could drill holes in the ends of the tanks and silicone the bukhead fittings right thru bothe ends of the tanks and put the nut on the other side and have the inlet to the cannister filter on the first tank and the spray bar on the last

[SamH]

Yeah, all the tanks will be on the same level. Very tempted to do this, will see how it goes at the time.

[the-obstacle]

The trick will be keeping the same area on the output pipe before and after the splits. If you're cannister output pipe is 12mm internally then you need to figure out the area (pi x (r*r)) of that and then make sure the 3 pipes areas add up to that amount that way there is no path of least resistance but the cannister pump doesn't get overworked either. Do the same for the intake of the cannister. It's not as simple as dividing 12 by 3 though as the area is quite a different number.

[Bilbo]

Its a flood waiting to happen. You will end up emptying one tank and over fill another and the flow only needs to be a tiny bit out.

It could possibly work if you got the flow pretty close and then fitted had a syphon between the tanks to keep them all level.

[suphew]

The cannister filter idea is a no go, it just couldn't work. With the cost of plumbing and the hassles/risks involved it would be far simpler to get a tank the length of all three and put some divider's in.

[~Shaun~]

Hi. I realise this is quite an old thread (and the point is likely moot by now) but I've done something similar to this by running a large-bore siphon between the tanks and then have the canister sucking out of one end and pumping back to the other end. There will be a slight difference in water level between the tanks, stepping down as you go from canister outlet to inlet and it pays to have clear siphons so you can check for air bubbles in them but it can be done.

I've used PVC tubing from hardware stores for the siphons and it will work fine if set up properly. It won't be high-flow though and basically biological filtration only as the flow will be too low to remove detritus. Obviously if the critters in each tank are small enough to fit through the siphon then a 'strainer' will need to be fitted. Also it pays to have the suck-end of the siphon cut in a 'V' so that it's less likely to have something suck onto it and block it.

Just my 2c.

[edit] I've also used Marley white PVC rigid pipe and two 90º elbows to make siphons. It looks a lot better but you can't see if any air is trapped in the top of the siphon so you need to mark each tank's running-level (with a newly-cleaned canister) on the tank and, if the levels change much then re-start the siphon. The siphon is started by submerging it completely in a tank, filling it up, then blocking both ends while it's positioned in place, either using your thumbs or corks / sparkling wine bungs or similar.

Good luck.