You may get away with this, but in general the pump curve of built-in canister filter pumps isn't very 'flat'. The canister filter manufacturers usually design the built-in pump as just large enough to work with the canister configuration, filter media, and hoses which are supplied with the filter as a cost control measure. Thus as you add extra plumbing fittings to the system, either in the form of add-on filter hose attachments like in-line heaters or UV units, or in this case in the form of lots of extra plumbing elbows and straight pipe length in the clean water return plumbing, the overall flow rate is going to drop. Thus you may find that your canister filter flow rate (and therefore the tank volume that the canister can effectively filter) winds up being cut in half by asking it to supply undergravel jet plumbing instead of just 'dumping' the clean water.
Undergravel Jets...
- Thread starter snytiger_92
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Just add a power head
Set up an UGJ system as you descibed but power it with pre-filtered power heads and use your idea to run the returns from the cannisters down through your background but empty directly into the aquarium at the level. That should accomplish most of wht you want.
I do have one question though. Since most oxygenation of the water takes place through surface agitation wouldn't this create a lower oxygen situation than preferred?
Set up an UGJ system as you descibed but power it with pre-filtered power heads and use your idea to run the returns from the cannisters down through your background but empty directly into the aquarium at the level. That should accomplish most of wht you want.
I do have one question though. Since most oxygenation of the water takes place through surface agitation wouldn't this create a lower oxygen situation than preferred?
Thanks for the response - melonie, you sound like a fellow engineer (that is a complement..LOL). I'm wondering if losing a little flow needs to be a concern since the Magnum alone is supposed to be enought filtration for a 100 gallon tank (looks like I need to pull out the old college fluid mechanics textbook!). Also, I'm relying on the plants to help reduce filtration requirements. I may set up the UGJ to the cannisters, and do a test-run with the tank half full - just to see what happens. Since both canisters have impellers, I can always build a shelf under the stand to elevate the cannisters as high as possible, to reduce the head.
Ghoti, you are dead on. Typically, oxygenation of the water takes place via surface agitatation. Also, during this process, CO2 is equallized to atmospheric concentrations. Since I'm going to heavily plant the tank, and I'll have plenty of light, and nutrients, the limiting growth factor for the plants will be lack of CO2.
Rather than ADD CO2, I'm going to attempt to up the CO2 level by heavily stocking the tank, and hoping that the fish resperation will supply the additional CO2. If this works correctly, I should get "pearling" on the plants of their photosynthesis output - oxygen. From the reading I've been doing, a tank with healthy, pearling plants can actually become "super saturated" with oxygen.
The only concern for the fish will be overnight, when the plants actaully USE oxygen. I figured I'd give this a shot, see how the fish and plants do (I will start off with the bio-wheels that came with the Magnum 350 providing SOME surface agitation). If the fish are at the top of the tank, gasping for air, I'll add more surface agitation.
If the plants don't pearl, then I'll try adding DIY CO2 (if that doesn't work, I'll have to pony up for pressurized CO2).
What do you think? Sound feasable?
Ghoti, you are dead on. Typically, oxygenation of the water takes place via surface agitatation. Also, during this process, CO2 is equallized to atmospheric concentrations. Since I'm going to heavily plant the tank, and I'll have plenty of light, and nutrients, the limiting growth factor for the plants will be lack of CO2.
Rather than ADD CO2, I'm going to attempt to up the CO2 level by heavily stocking the tank, and hoping that the fish resperation will supply the additional CO2. If this works correctly, I should get "pearling" on the plants of their photosynthesis output - oxygen. From the reading I've been doing, a tank with healthy, pearling plants can actually become "super saturated" with oxygen.
The only concern for the fish will be overnight, when the plants actaully USE oxygen. I figured I'd give this a shot, see how the fish and plants do (I will start off with the bio-wheels that came with the Magnum 350 providing SOME surface agitation). If the fish are at the top of the tank, gasping for air, I'll add more surface agitation.
If the plants don't pearl, then I'll try adding DIY CO2 (if that doesn't work, I'll have to pony up for pressurized CO2).
What do you think? Sound feasable?
sand....
Just thinking....I know Malawi cichlids natural habitat is sand, I am not sure about others, but if you want to set things up so the fish will be the happiest you may want to stay away from undergravel filters and jets. Sand doesn't work very well with them. :idea2:
Just thinking....I know Malawi cichlids natural habitat is sand, I am not sure about others, but if you want to set things up so the fish will be the happiest you may want to stay away from undergravel filters and jets. Sand doesn't work very well with them. :idea2:
Actually, I'm debating about going with cichlids or not. Most likely will go with tetras.
I know undergravel filters don't go well with sand, or plants, but from what I've been reading, undergravel jets seem to work BEST with sand (I'll be using a mixture of pool filter sand, flourite, and profile). They keep enough current along the bottom of the tank to keep waste from settling on the sand.
I plan on positioning the jets to "blow" waste towards the canister filter intakes.
I know undergravel filters don't go well with sand, or plants, but from what I've been reading, undergravel jets seem to work BEST with sand (I'll be using a mixture of pool filter sand, flourite, and profile). They keep enough current along the bottom of the tank to keep waste from settling on the sand.
I plan on positioning the jets to "blow" waste towards the canister filter intakes.
I agree that in your particular situation, you can probably get away with stacking the UGJ plumbing on the discharge of your canister filters. To help yourself somewhat I'd consider upping the hose and pipe size used on both filters and UGJ's to 3/4" though to try and minimize the additional head loss.
As to the overnight oxygen scenario, you can always run a bubble wand on a timer if there is an 02 problem! While bio-wheels are great for ammonia and nitrates and O2, they're also guaranteed to reduce your dissolved CO2 by atmospheric exposure and therefore might not be the best choice given your plant count.
As to the overnight oxygen scenario, you can always run a bubble wand on a timer if there is an 02 problem! While bio-wheels are great for ammonia and nitrates and O2, they're also guaranteed to reduce your dissolved CO2 by atmospheric exposure and therefore might not be the best choice given your plant count.
Melonie...
Thanks!! You've given me an epiphany! I had completely disreguarded the fact that if I need to add CO2, I was going to use an inline reactor on the output side of each canister, to feed into the UGJ. The reactor for the Magnum I was planning on putting after the split in the line which feeds the bio-wheel (on the way to the UGJ).
This may actually reduce the flow too much.
Perhaps a better option would be to run the Magnum as it should be (with the exhaust low in the tank), and use the XP2 to run the entire UGJ (say 6 jets), and put a single CO2 reactor in line with it only.
Do you think a single Magnum 350 with bio-wheel will be enough biological/mechanical (not planning on using chemical) filtration for a heavily planted and stocked tank? I know I'll get some additional mechanical filtration from the XP2, but if I have it hooked to the UGJ with a CO2 reactor, I don't want to depend on it.
Thanks!! You've given me an epiphany! I had completely disreguarded the fact that if I need to add CO2, I was going to use an inline reactor on the output side of each canister, to feed into the UGJ. The reactor for the Magnum I was planning on putting after the split in the line which feeds the bio-wheel (on the way to the UGJ).
This may actually reduce the flow too much.
Perhaps a better option would be to run the Magnum as it should be (with the exhaust low in the tank), and use the XP2 to run the entire UGJ (say 6 jets), and put a single CO2 reactor in line with it only.
Do you think a single Magnum 350 with bio-wheel will be enough biological/mechanical (not planning on using chemical) filtration for a heavily planted and stocked tank? I know I'll get some additional mechanical filtration from the XP2, but if I have it hooked to the UGJ with a CO2 reactor, I don't want to depend on it.
Again, using a bio-wheel is going to aerate your tank water and encourage the CO2 you just injected to escape. Strictly gut reaction, but you might consider loading up the Rena's upper tray with bio-noodles instead and not using the bio-wheel approach for bio-filtration if you're injecting CO2.
Since I have owned a Rena canister in the past, I would be highly dubious of its ability to supply a UGJ header with anywhere near enough flow rate to create a useful current above the sand in the bottom of your tank. My XP-2 has a spec of 300gph, which I actually measured at more like 250gph with normal media in the trays. I would speculate that if also connected to an UGJ header that the flow rate will probably drop even further to the 200 gph ballpark or below. On the other hand, I would take a wild guess that in order to generate enough current above your sand bottom to move debris you'll need something like 600-800 gph through your UGJ system given your 100 gallon tank. A rough guess on the results of using your Rena to drive a UGJ header is that the bottom 1" of tank water will move at a rate below 1" per second. If your tank is 18" deep every 1" of bottom water movement per second requires 1.5 x 1/12 x 1/12 ft = .0104 ft^3/sec = 37.5 ft^3/hr = 315 gph
I don't have personal experience with the Magnum canisters, but from all of the reviews I have seen they have an awesome mechanical filtering capacity of the water that actually passes through them. Therefore your question basically boils down to whether or not you wind up with a sufficiently rapid turnover rate, i.e. actual canister filter gph divided by tank capacity, to stay ahead of the tank's contamination rate. The typical rule of thumb figure is five turns per hour, or in the case of your 100 gal tank 500 gph versus your Magnum 350's 350 gph spec and probably 300 gph actual when loaded with normal media. Three turns per hour is enough for some tanks, but not enough for others ... depending on degree of tank stocking, plant density etc.
I'm sure you remember the engineering problem of trying to solve an equation with too many variables LOL ! My vote is to give it a try - you can always buy a separate 600-800 gph submersible pump/powerhead to drive your UGJ header if things don't actually pan out the way you envision trying to use the canister filter pump(s) to also drive your UGJ header.
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Since I have owned a Rena canister in the past, I would be highly dubious of its ability to supply a UGJ header with anywhere near enough flow rate to create a useful current above the sand in the bottom of your tank. My XP-2 has a spec of 300gph, which I actually measured at more like 250gph with normal media in the trays. I would speculate that if also connected to an UGJ header that the flow rate will probably drop even further to the 200 gph ballpark or below. On the other hand, I would take a wild guess that in order to generate enough current above your sand bottom to move debris you'll need something like 600-800 gph through your UGJ system given your 100 gallon tank. A rough guess on the results of using your Rena to drive a UGJ header is that the bottom 1" of tank water will move at a rate below 1" per second. If your tank is 18" deep every 1" of bottom water movement per second requires 1.5 x 1/12 x 1/12 ft = .0104 ft^3/sec = 37.5 ft^3/hr = 315 gph
I don't have personal experience with the Magnum canisters, but from all of the reviews I have seen they have an awesome mechanical filtering capacity of the water that actually passes through them. Therefore your question basically boils down to whether or not you wind up with a sufficiently rapid turnover rate, i.e. actual canister filter gph divided by tank capacity, to stay ahead of the tank's contamination rate. The typical rule of thumb figure is five turns per hour, or in the case of your 100 gal tank 500 gph versus your Magnum 350's 350 gph spec and probably 300 gph actual when loaded with normal media. Three turns per hour is enough for some tanks, but not enough for others ... depending on degree of tank stocking, plant density etc.
I'm sure you remember the engineering problem of trying to solve an equation with too many variables LOL ! My vote is to give it a try - you can always buy a separate 600-800 gph submersible pump/powerhead to drive your UGJ header if things don't actually pan out the way you envision trying to use the canister filter pump(s) to also drive your UGJ header.
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