Opinions/Help Building my own Canister Filter for a 125

[RyanRX7]

So I've been working on building my own canister filter for my 125 NPT. The reason is because I wanted a 6' spray bar to provide circulation for the entire tank, thus requiring a pump with some decent flow. Completed my build today and tested it, problem is the bucket I used is too thin and the input flow is to slow.

I originally had a single 3/4" inlet to the filter, and a 3/4" outlet going to my Iwaki MD40RLT pump (I'm guessing about 600-650 GPH after head). Yea, didn't think it through and that 3/4 inlet wont keep up AT ALL Sooo, I had an extra 1/2 bulkhead sitting around and I added that too, still not enough (after some additional research I found the flow rates for those bulkheads are 350 and 150 GPH). The resulting pressure created by the pump sucking the water through the filter was strong enough to warp the bucket's shape while on The bucket I used as a translucent 3.5 gallon from Lowes, looks like it's not going to be strong enough to handle the pressure the canister filter is going to put out.

My idea thus far is to get a heavy duty 5 gallon ( 90 mil thickness as opposed to standard 70 mil on your average plastic bucket), and 2 3/4" bulkheads. The reason I'm trying to stay with the 3/4" bulkheads is because I'm using 5/8" hose to allow me to use the quick disconnects like on a Magnum 350 filter. I have to have disconnects on the input lines so I can disconnect them to spin off the lid to the bucket/filter.

Is it normal for a canister filter to carry pressure inside and have the pump suck the water, unlike a sump that is open? Is 650 GPH too much flow on a 125 NPT?

Any other ideas to help improve the design would be sweet, perhaps someone knows of a larger hose disconnect I can use?

[Diana]

Yes, the pump can collapse the bucket.
You could probably use some other form of disconnect, for example PVC unions. These are available in all the regular PVC sizes. A ball valve above it would hold the water in the pipe so that when you reconnected it would self-siphon and fill the bucket.

650 gph is pretty good filtration for a 125, I would not go any lower, but would probably add a couple of power heads to increase circulation if there are any dead spots.

[RyanRX7]

I'll look into the PVC unions, thanks for the suggestion Diana

[tropicalfish]

Unless you have a good way of attaching the bucket lid very securely, I would not have the pump on the intake side.

[RyanRX7]

The pump is on the return side of the filter. The lid is a Gamma Seal screw on lid that fits very tight and is air and water proof.

[Hoppy]

When you consider the consequences of a major failure of a DIY canister filter I think it isn't a good project to tackle. Why not look at one of the Ocean Clear filters, http://www.aquariumguys.com/oceanclear.html which many people use and like? At least you could use this as a "blueprint" for how to design a good one.

[RyanRX7]

Hoppy, I must admit that I feel pretty stupid. I had no idea such filters existed. I might just go ahead and get myself one and save myself the trouble. Thanks for letting me know about these

[Hoppy]

I didn't know about those filters for many years. I think the first time I realized what they were was about 2 years ago. There are two brands of them, as far as I know, but I don't know what the other brand is.