the infamous 5 gallon diy canister filter. can it be done????

[CWO4GUNNER]

Well assuming you don't have a pin hole leak and negative pressure is causing air to come out of solution (Boyle's law NOT cavitation:shakehead all you really need is a simple $9 digital wall-plug timer to turn your pump off and on a few times automatically within a 24 hour period. The off time can be set as sort as 2 minutes, during which the pressure from the tank will force all the air out of the canister and the cycle starts over just like on the FX5. I had mine set to shut down every 6 hours for 2 minutes in a 24 hour period and it worked great becasue the rate of air coming out of solution will be slow and constant.

However you wont be able to determine that rate until you set your tank in relation to your aquarium water level. This is because the negative pressure your pump is creating is only relative to the positive pressure exerted on it while running. Because I had my DIY canister only 10 inches below my tank water line the pump had a substaintial amount of negative pressure relative to the small amount of positive pressure exerted on it. If I placed the canister lower air coming out of solution would decrease becasue positive pressure would increase acting against negative pressure which would decrease and conversely as I set the canister higher the opposite would happen.

So when you set up first pick a spot relative to height of your tank waterline that your canister can handle pressure without bulging or leaking, you will notice the difference as you lift the canister high or low while running the canister will either bulge on the ground or go concave toward the top of the tank. Try and pick the spot that is in between for safety against rupture or loss of prime. Then and only then deal with air coming out of solution as you may not have any at all like most weak motor canisters.

 

[Sploke]

so i plan on doing another thread diy for altering the sump alarm to switch the pump off automatically when the water reaches a certin level and come back on automatically when the water comes back up.

Just use some float switches and a relay to comtrol a pump. My drip change system is below-grade so I need to pump water out of the sump rather than just letting it overflow, so I have two float switches that turn the pump on and off at set levels.

 

[CWO4GUNNER]

Only because a sump is not a closed system and flooding is a real and potential possibility. A canister is a closed and sealed system with substantially less possibility of flooding only causing a pump failure in damage rather then alternative $$$. Having to drill more holes for alarm and switching devices only further compromises a canisters integrity and electrical safety, all a canister needs is a timer.:thumbsup:

And besides if the canister catastrophically fails under pressure due to structural shortcomings, by the time an alarm or switch kicks in at 2am the damage at least most of it would have already been done, not to mention the possibility of electric shock concerns.

 

[iamvictor2k]

the filter is complete. i am now testing on the tank.



this is the filter with the pump running



this is the filter with the pump shut off.

there is not very much pressure at all either way. yes it does move the lid about 1/2 to 3/4 of an inch up and down but its flexible you can do that with your hand. i had been holding off doing a water change for about 2 and 1/2 weeks to complete this filter so i could see the actual change in the water. it was almost instantly clear vs the brownish color it was before. there are no leaks what so ever. i plugged and unplugged it about 20 times no leaks. i did have to modify the fittings on the lid of the bucket though.

I had to cut the 3/4 inch threaded nipple adapter in half on the threads so i could put another rubber washer on the top of the bucket for the negitive pressure and then the female adapter was threaded on the modified adapter and pulled both of the seals tight agenst the lid and its self. there is now no nut instaled on them. o i also filed the embossed letters of the adapter fitting so i would be sure to have a smooth seal.

the lid holds the pressure fine from the weight of the water that is in the 3/4 inch tubes. the pressure does not come from the tank just from the height of the tubes.

i filled the hole inside the bucket where the tube was running with blue filter media and tightly packed poly fill.

any questions i will be glad to answer.

i will post my parts and expense list later this week.

any more questions i will be glad to answer.

 

[Squawkbert]

...The FX5 is the only over the counter canister filter that generates negative pressure that exceeds the positive pressure of all 31 inch tall tanks and it can be proven by simple removing the inlet hose to the canister while it is running and no water will exit the open intake port of the canister, in fact the canister will pump out into the tanks until it looses prime and then ungulate as it looses and regained prime from the bottom of the empty canister. No other over the counter canister can do this not even the Magnum 350 as water will simply pour out of the canister with the the far weaker pumps unable to out pace the tanks pressure.

This is why the FX5 has to shut down every 24 hours to purge air that has been literally sucked out of the water due to negative pressure in excess of the tanks positive pressure. The reason is the combination of the powerful pump motor and its rotary style impeller providing almost positive displacement, unlike a paddle blade impellers that all the competition uses allowing cavitation and non-positive displacement against water.

I think my Eheim 2215 vacuums some air out of the water column too. Its hoses run from the bottom of the tank stand over the top of my 46g bow (I think the stand and tank are about 24" ea. so that's at least a 4' head less the height of the canister). I admit I have not shut off the upper inlet ball valve and tried just removing the inlet hose, but I'd wager that (at least for a while after a cleaning) it wouldn't leak either. If I happen to remember to try it next time I'm pulling it, I'll let you know. If it fails, I may upgrade to a 2217 impeller and try it again...

Eheim Classics and Fluval FX are (IMO) the best designs out there for canisters. I find Eheim's attempts to improve on this series to be a little bit sad.


PS - in general, I really have enjoyed this thread. Good work, good discussion... I'm crossing my fingers and hoping for no flooding.

For those who may still be a little foggy on water pressure - it's strictly a function of depth. The larger the verticle distance between the tank's water line and the canister, the higher the pressure within the canister (when the power to the pump is off). That's (usually) the most critical design accomodation to be made.

PPS - For those who get the above... it's the opposite for powder storage; tank diameter is proportional to side wall pressure. That's why grain silos are really tall and liquid storage tanks are really wide. I've been learning lots about powder flow and such lately, so I thought I'd share that little nugget as it bent my mind for a day or two when I first encountered it.

 

[CWO4GUNNER]

Since it is working and your committed to trusting it, all that is left to do its to wait and see.

I do recommend that you at least remove those nails, try doubling up on the lids and trim the J hook bolts (the J end) so that they will tighten down far enough without the need for the nails.

Also since you are using an overflow container, that is where I recommend you place a simple PWC bilge pump/alarm available for about $25-$35 as it would be very good insurance against a canister that it telling you its under allot of strain.

Glad to see that it works, hope you have leaned allot as I did on my DIY, and hope for your and your family's sake it works great without flooding.

 

[Star_Rider]

hey it got my wheels spinnin.
I ham going to see if I can mod a salt bucket .. heavy duty with reinforced lids.

 

[CWO4GUNNER]

hey it got my wheels spinnin.
I ham going to see if I can mod a salt bucket .. heavy duty with reinforced lids.

remember the challenge will always be the lid seal. If there is a lid rim slot see if you can find some thin neoprene rubber to cut a gasket and place it inside joint at both ends with neoprene glue, that way it will not take much lid clamp pressure to create a water tight seal rather then having to clamp the lid so tight. Also consider a clamping system that uses the bottom of the canister like 4 long car battery clamps with turn-buckles that hook from the bottom of the canister to the top using two plywood rings.

 

[Star_Rider]

remember the challenge will always be the lid seal. If there is a lid rim slot see if you can find some thin neoprene rubber to cut a gasket and place it inside joint at both ends with neoprene glue, that way it will not take much lid clamp pressure to create a water tight seal rather then having to clamp the lid so tight. Also consider a clamping system that uses the bottom of the canister like 4 long car battery clamps with turn-buckles that hook from the bottom of the canister to the top using two plywood rings.

these come with a seal..unsure if it is neoprene.

the lids are ribbed(think wagon wheel here) with a strike point on them to use a mallet/hammer to open the bucket.

the rim of the bucket is also heavy duty..I think you are correct the challenge will be to devise a clamping system.
I will take a closer inspection of these when I go home.

 

[xsdbs]

how's this working for you so far?