Gravel vacuum

I don't have a python but want to make something that works the same to remove sloughed off bacteria in the bottom of my rotating biological contact filter tank for my 500 gallon recirculating system.

Isn't the python simply a hose with one end siphoning and on the other end a 't' with one end of the 't' water running in and the other side of the 't' the water running out creating suction? Or does one need a valve to shut off flow briefly to fill the hose and create suction?

if that is the case it seems I could easily make one myself with some hose and PVC parts and a thread to hook a garden hose I have that is connected to my water supply.

No issues with cleaning the bottom of 300 gallon circular tank as it's self cleaning with settleable solids going down the drain via centripedal flow to a 55 gallon drum clarifier and the suspended solids are removed mid depth via a u tube siphon.

I've never owned a python either, but it sure seems like it could be a nice DIY. My understanding of the operation of one is basically the same as yours. Not having one though, I'm not sure if it uses a standard "T" or if it is a sweeping "T", or even an angle more acute than 90 degrees. The pressurized line may also neck down to a smaller inside diameter at the intersection to increase velocity, thereby maximizing the venturi effect. The siphon pumps we use where I work at are standard "T's", but we also use steam pressure to create the siphon instead of water pressure. I believe the ID is necked down on the pressure line at the intersections of our steam operated ones.

While I may not be completely certain of the exact design of the python gravel vacuum, I am certain that you have one incredible sounding system. I understand how a rotating biological contactor works, but I'm having trouble understanding how the whole system fits together. Do you have any pictures or diagrams that are easy to come by that show how it works as a whole?

Thanks;

Steve.

I ordered this as it seemed to have good reviews last month in anticipation of need for my 55 gallon. I think it is like the Python.

http://www.amazon.co...duct/B000YAJKL6

I used it once and have some issues with it. First of all it does work as intended but the plastic siphon, in my opinion, is too big in diameter and does not provide enough suction action to get the little stuff agitated and flowing out of the tank. Second the plastic siphon itself, being too large in diameter, is difficult if not impossible to get around all the smaller places in the tank. I have to move too much stuff which I don't like to do because it messes with the plants. As for the water exchange, it does work well but as it is hooked to the sink faucet it does not allow for you to pre-treat the water for chlorine and choramine.

So, I have gone back to my old hose and bucket method. But that has problems too as the smaller hose makes too much suction and easily sucks up the gravel. But it does get to all the various locations inside the tank much easier. I went searching for a smaller diameter plastic suction tube last week so am still trying to find/make a perfect siphon.

Usil

Edited by Usil, 03 October 2011 - 04:19 AM.

As for the water exchange, it does work well but as it is hooked to the sink faucet it does not allow for you to pre-treat the water for chlorine and choramine.

Pretreating is not important. Chlorine and chloramine are long term poisonings. If you empty your tank, fill it, and then treat the water after the tank is full again, all within half an hour or an hour or so, then that's not a long enough time period for your fish to have any problems because of the chlorine/chloramine. What really matters is if you don't remove the chlorine and it stays there for a whole day, or chloramine for multiple days, and then your fish are exposed to it not only for many hours at a time, but every single occasion that you do a water change (every week, two weeks, or so). Chronic gill damage matters. Half an hour's worth of chlorine doesn't.

So, I have gone back to my old hose and bucket method. But that has problems too as the smaller hose makes too much suction and easily sucks up the gravel. But it does get to all the various locations inside the tank much easier. I went searching for a smaller diameter plastic suction tube last week so am still trying to find/make a perfect siphon.

Usil

With just one type of substrate, you may be able to get close to the "perfect gravel vacuum". I've got too many different types of substrate. What works well for gravel, will suck up fine sand, but if it doesn't suck up fine sand, well...it won't suck up anything. Does your vacuum wand on your "hose and bucket" system have a flare for the end of it? My vacuum wand has a 1" ID and my hose has a 1/2" ID. That combination is actually too much suction, but when I use the flare on the end of the vacuum wand it seems to work as good as I can expect. Mine also goes through two 3/8" check valves for the hand primer, so I'm sure that decreases the suction some too. If I remember right from the photos and video, your substrate is pea gravel size or a little smaller. My vacuum isn't too bad at picking up that size of gravel with the flare on the end of the wand. It originally came with 7/16" ID tubing instead of 1/2". If that were being used, I'm almost certain it could be a combination that would work for you. Here's what I ended up buying.

http://www.amazon.co...17651830&sr=1-3

I do have to clean some stuff out of the internal screen after each use, but so far I really like it. It does feel a little cheap, but it's already been through enough water changes and cleanings that if it broke today, I'd probably just go ahead and buy another one.

Hope this helps. Good luck on your search for the perfect gravel vac.

Steve.

My eternal search for the perfect tank suction cleaner is like my search for the best Crème Brûlée or the best Lasagna. I know it's out there some where but I just have not found it yet.

Usil

Pretreating is not important. Chlorine and chloramine are long term poisonings. If you empty your tank, fill it, and then treat the water after the tank is full again, all within half an hour or an hour or so, then that's not a long enough time period for your fish to have any problems because of the chlorine/chloramine. What really matters is if you don't remove the chlorine and it stays there for a whole day, or chloramine for multiple days, and then your fish are exposed to it not only for many hours at a time, but every single occasion that you do a water change (every week, two weeks, or so). Chronic gill damage matters. Half an hour's worth of chlorine doesn't.

Years and years ago, I killed a nice group of cardinal tetras doing this. Took them less than 20 minutes to keel over. I'll never do that again.

While I may not be completely certain of the exact design of the python gravel vacuum, I am certain that you have one incredible sounding system. I understand how a rotating biological contactor works, but I'm having trouble understanding how the whole system fits together. Do you have any pictures or diagrams that are easy to come by that show how it works as a whole?

Thanks;

Steve.

Steve,

Unfortunately I don't have any recent photos to post yet where I've made modifications as my regular computer and scanner is offline due to some problems with the Internet.



The system's simply a 300 gallon circular galvanized stock tank for the fish I got for free and coated with an epoxy. Coating with epoxy is not optimum but I got it for free. If I had a choice I would purchase a plastic stock tank from one of the farm supply stores. The galvanized tank also has ribbings that collect particles which is not optimum.

In a separate 180 gallon oval plastic tank right next to the stock tank is the RBC that after treating the water with the microbes overflows back into the 300 gallon tank due to being higher than the fish stock tank. It's simply a 3 inch pipe connected via a Uniseal that dumps into the stock tank. Initially I had the RBC in the same tank as the fish, but doing that you don't get maximum efficiency of the RBC. This is due to it getting clogged with particulate matter which is a more condusive environment for competing heterotrophic bacteria vs. the autotrophic you want (nitrosomonas and nitrobacters).


In the stock tank (fish tank) there is a center drain which is 4 inch diameter hole cut which fits a 3 inch Uniseal perfectly. A 3 inch piece of PVC goes through the Uniseal and is capped with a slip in shower drain with the plastic grate cut out for better gravity flow. I cut a homemade plastic washer out of the plastic wall sheeting you can get at a building supply store to keep the pipe and shower drain from pulling through. There just isn't enough lip on the shower drain to prevent pull through.

An anti-vortex circular cover is cut out of some quarter inch plastic sheeting that I got for bottom diffusers in ponds (just a circle). It's mounted with three stainless steel screws and there is a half inch gap between it and the top of the shower drain to keep fish out. A membrane diffuser plate is mounted to the top of the anti-vortex plate but I haven't tried it yet.

The drain pipe (3 inch PVC) drops to the floor to an elbow and the vertical height is adjustable with a rubber sleeve and clamps to compensate for the downward bulging of the tank when it's full so as not to put too much pressure on the PVC that is resting on the floor.

BTW all tanks are set up off the floor with cinder blocks.


The 3 inch PVC then runs parallel to the floor with an inline gate valve to shut off the tank water when cleaning the connecting 55 gallon clarifier. The 3 inch PVC runs up into the bottom of a 55 gallon drum (clarifier) which again is slid through a Uniseal and capped with an ungrated shower drain and plastic washer to hold it in place.

I don't use bulkhead fittings anymore. Uniseals are superior, easier to install, and are much much cheaper.

The connection that runs up into the clarifier drum is actually a 't' with the horizontal tail end connected to a plastic hose for draining the clarifer tank when spraying off the deer fence netting with a garden hose connected to the water supply. The cleaned netting is temporarily placed into an adjacent empty drum. Once the clarifier tank sprayed out and drained the netting goes back into the tank.

The drum is packed with deer fence netting to collect suspended solids as the water flows upward pulled by a 30 watt pump lying on top which moves the water to the frame of the RBC where it drops on the baffles to turn it. I also put a couple of filter pads under the pump for additonal filtration.

The RBC can maintain about 100 lbs. of fish.
'
There's also a 'u' tube siphon that pulls water from the fish tank to the bottom of the clarifer to catch suspended solids vs. the settleable the center drain does. I'm hoping to forego the additional 30 watt pump used for the homemade spray bar and instead use the diffuser which could kill two birds with one stone. I've been using an agitator in the center of the tank but it uses much more power than the mere 30 water pump that runs the system. The diffuser is something I haven't tried yet hower.

The spray bar which consists of a horizontal and vertical axis does an awesome job of creating centripedal flow and you can watch a sinking fish pellet slowly makes its way in smaller and smaller circles to the center drain.

Edited by az9, 03 October 2011 - 03:17 PM.

Years and years ago, I killed a nice group of cardinal tetras doing this. Took them less than 20 minutes to keel over. I'll never do that again.

Really? I had never tried it on cardinal tetras, but it makes sense that some fish would be more sensitive than others. It'd be neat if people could list the fish they've had problems with chlorine with, and the ones that are hardier against it.

The fish I've chlorinated temporarily with no problems include:
Etheostoma spectabile, Elassoma gilberti, Xiphophorus hellerii, Xiphophorus maculatus, guppies (wild and fancy type), Betta splendens, Trichopsis pumila, and probably a few more but I can't remember at the moment. I used to dechlorinate strictly, but have gotten laxer and laxer as it seems to have no effect on the fish species I was keeping at the time. That list at least it's safe to temporarily chlorinate.

I wish I could remember what technique I was using when I had the neon tetras at DH 20. I think I dropped the dechlorinator drops in the bucket of water before adding it to the fish tank. I can't remember.

Edited by EricaWieser, 03 October 2011 - 03:01 PM.

Erica- The trouble is, tap water does not have a consistent chlorine content from municipality to municipality or day to day within the same municipality. Fish sensitivity is not the only factor. You'd have to do trials with water at a standardized chlorine content to determine fish sensitivity. I too tend to dechlorinate water in the tank, but it does carry some risk.

az9- That's a neat set up! It looks like it could handle a heck of a bioload. I'm glad to hear the Uniseals work well for you- I've considered them in the past but shied away because I wasn't sure how durable they are.

AZ9, that is one ingenious set up. I apologize if you already told us, but what do you raise in that system? It looks like something an old retired guy might take a crack at. Have you ever tried to make the whole thing run on gravity? My imagination is fired up.

Regarding pretreating for chlorine, it has been a long time since I have had to deal with municipal water but I don't know if pretreating is unimportant. There are so many variables to take into consideration I am not sure a species list would tell you much. You have a situation where you can get away with it, so that's good for you, but its a dangerous experiment to recommend.

On the other hand, I am enough of an old mossback to think we can get carried away with some of the ultra-modern aquarium tech stuff. My advice, seek out the advice of your local aquarium shop - they should have a handle on the various water quality issues in your area. Mine even knows the various well water and softener issues around my county.

az9- That's a neat set up! It looks like it could handle a heck of a bioload. I'm glad to hear the Uniseals work well for you- I've considered them in the past but shied away because I wasn't sure how durable they are.

About 100 lbs. of bioload. The Uniseals are made of Dupont Acryln, rated to 40 psi and warranted for 25 years. They are immune to cold and will not harden and hold pressure and vacuum.

A tip to know if you are going to use them though: It's a real bear to slide a pipe through them. The trick is to not only vaseline the pipe but cut the end at a very sharp angle to decrease initial surface area to make the pipe easier to slide through. Then you can cut the pipe anyway you want to after it's through.

AZ9, that is one ingenious set up. I apologize if you already told us, but what do you raise in that system? It looks like something an old retired guy might take a crack at. Have you ever tried to make the whole thing run on gravity? My imagination is fired up.

Although I've modified it a little I can't take credit for it. It comes from a book called Small Scale Aquaculture by Steve VanGorder.



Not sure if you could run the whole thing on gravity as I've tried. But running the entire thing on a 30 watt mag drive pump with an efficient air pump is close enough for me.

I raise bluegills and yellow perch in mine presently, buy if I am successful in producing a good smallmouth hatch this coming spring I will overwinter some smallmouth in one too. I bring YOY fish in for the winter to get a few extra inches on them vs. none in the ponds under the ice.

I'm setting up a local high school with a system in a week or so and providing the fish and feed. As president of our state aquaculture association I'm always looking for ways to get people interested in aquaculture. I can't think of a better way than to plant the bug in some students. It's also a fun way to learn about science.

Thanks for the info. I might have to give this a try. We are thinking of moving to an area with a lot of artesian springs, so I might be able to do this without electricity. Worth a try.

Artesian spring, That would probably do it. I've been wracking my brain trying to come up with and idea that could do it by pure gravity, but just couldn't think of anything. Although, if the spring has enough flow year around to continually replace the water, you might not need biological filtration at all.

AZ9, that really is an impressive set up. Thank you so much for sharing the explanation and photo. It's also got my interest up in thinking about trying something like that eventually.
Have you seen the prices they are asking for used copies of that book through amazon.com? They're asking $900.00 and $1100.00 for used copies of it. The website; http://www.altaqua.com/index.htm lists it for $22.95 but it is out of stock. I think I'll keep an eye on it and order one for $22.95 when they get some back in stock.

Thanks again for sharing and good luck with the smallie hatch in the spring.

Steve.

Edited by frogwhacker, 04 October 2011 - 09:41 AM.

http://www.ebay.com/...Nonfiction_Book

Also out of stock, but they are accepting orders:
http://www.aquaticec...ale-Aquaculture

The python has been "replaced" by the aqueon unit, which seems identical.

the venturi feature on both is a waste, I always remove it and send water via the tap to the tank and then once the tube is filled I drop the end from the sink outside - no water waste.

If you're super concerned about chlorine poisoning, you can always add a drop of dechlorinator to the tank when filling the hose to neutralize any Cl that makes it into the tank. FWIW, in 20+ years I've never had an issue in terms of just putting dechlorinator into the tank while the new water was being pumped in (by re-attaching the python to the sink). Replacement gravel extentions for both the python and aqueon are available in many sizes.

The other methods of mulm removal are a waste of time (e.g. battery operated ones), and besides, any time you change water is good.