I'm in the process of designing an undergravel system to clean the gravel without a siphon. Basically a 1/2 pvc pipe grid with a screen on top, then gravel. It would be designed where the gravel could just be stirred up and debris would get sucked down into the pvc pipe, out of the tank and into a canister filter designed for larger waste. A polishing filter might be incorporated as a second stage. This would only be for occasional use but I would incorporate a secondary pump for constant operation (maybe revers flow under gravel filter type of operation).
Here is what I have so far.
This is for a 55 gal corner tank and was built to fit the bottom. A T has been added midway and a pipe that reaches the top of the tank inserted.
Note, this tank has a canister filter so this doesn't need to handle general tank filtration. This is not meant to eliminate water changes, but rather just to avoid having to clean the gravel with a gravel vac.
My first trial ended in failure (maybe). I'm not sure if you can see in the picture but the pipes have many 1/8" holes drilled (maybe 50 per foot in the center pipes, maybe 100 per foot in the outer pipes. I put it in the bathtub and pumped water into it to test. I tried a cheapo pond pump that is maybe 300 gph. There was barely a trickle of water from a few of the pipes. I then tried a high pressure heavy duty marine pump (300gph at 50psi with a 35 foot lift). It also provided just a trickle of water from some of the pipes. I thought the problem might be that there is no back pressure from being in a full tank. I filled the tub and feed from a 5 gal bucket with malachite green added (only dye I had handy). After about 10 seconds of operation (I guess to fill the pipe system with colored water) there was some dye water coming out of all the pipes but just a very small amount at the outer pipes and not a lot more on the inner pipes.
So going with a couple of thousand gph pump is probably out of the question (too much for a 55 gal and probably too expensive). All I know to do is replace the pipes (luckily the cheaper part) with pipes that have a lot less holes drilled to increase pressure. Does it even matter if there is much pressure? If there is 300 gph going under the gravel, will that be enough to suck up the stuff from the gravel?
The other question is what to do with it when it is not in gravel cleaning mode. I was thinking of making the system sealable. I could pump air into the pipe system to avoid a anerobic bacteria bomb. I was also thinking a power head to run it in a reverse flow setup. Would that have the same problems due to the low pressure? Maybe do both (air pumped into the system and a reverse flow?
Any thoughts, ideas or sugestions would be greatly appreciated.
Also, I was going to get a marine land maxi-jet pro 1200 (also about 300gph if I'm not mistaken). I have no idea if it is reversible? Would that work as a power head in a reverse flow setup?
Doing a little more looking, a larger pump for gravel cleaning might be doable (i'm seeing ones that are up to 1500 gph that might be affordable down the road). I will be draining the tank for other reasons within the next week (its active with fish in it so its got to be a quick job). I want the pipe system in place, even if the pump problem isn't worked out but I need the pipes as they need to be. It will be quite a job to tear the tank down to remove it again. I could seal and pump air in to avoid an anerobic bomb and or do the reverse flow with a power head for now?
Here is what I have so far.
This is for a 55 gal corner tank and was built to fit the bottom. A T has been added midway and a pipe that reaches the top of the tank inserted.
Note, this tank has a canister filter so this doesn't need to handle general tank filtration. This is not meant to eliminate water changes, but rather just to avoid having to clean the gravel with a gravel vac.
My first trial ended in failure (maybe). I'm not sure if you can see in the picture but the pipes have many 1/8" holes drilled (maybe 50 per foot in the center pipes, maybe 100 per foot in the outer pipes. I put it in the bathtub and pumped water into it to test. I tried a cheapo pond pump that is maybe 300 gph. There was barely a trickle of water from a few of the pipes. I then tried a high pressure heavy duty marine pump (300gph at 50psi with a 35 foot lift). It also provided just a trickle of water from some of the pipes. I thought the problem might be that there is no back pressure from being in a full tank. I filled the tub and feed from a 5 gal bucket with malachite green added (only dye I had handy). After about 10 seconds of operation (I guess to fill the pipe system with colored water) there was some dye water coming out of all the pipes but just a very small amount at the outer pipes and not a lot more on the inner pipes.
So going with a couple of thousand gph pump is probably out of the question (too much for a 55 gal and probably too expensive). All I know to do is replace the pipes (luckily the cheaper part) with pipes that have a lot less holes drilled to increase pressure. Does it even matter if there is much pressure? If there is 300 gph going under the gravel, will that be enough to suck up the stuff from the gravel?
The other question is what to do with it when it is not in gravel cleaning mode. I was thinking of making the system sealable. I could pump air into the pipe system to avoid a anerobic bacteria bomb. I was also thinking a power head to run it in a reverse flow setup. Would that have the same problems due to the low pressure? Maybe do both (air pumped into the system and a reverse flow?
Any thoughts, ideas or sugestions would be greatly appreciated.
Also, I was going to get a marine land maxi-jet pro 1200 (also about 300gph if I'm not mistaken). I have no idea if it is reversible? Would that work as a power head in a reverse flow setup?
Doing a little more looking, a larger pump for gravel cleaning might be doable (i'm seeing ones that are up to 1500 gph that might be affordable down the road). I will be draining the tank for other reasons within the next week (its active with fish in it so its got to be a quick job). I want the pipe system in place, even if the pump problem isn't worked out but I need the pipes as they need to be. It will be quite a job to tear the tank down to remove it again. I could seal and pump air in to avoid an anerobic bomb and or do the reverse flow with a power head for now?
