The DIY gravity filter, From start to Finish. COMPLETED!!!

[FRESHBAIT]

With everyone starting to build bait tanks, and all the questions on gravity style filters.  I decided I'd do a DIY gravity filter, from start to finish so that everyone can see how to make one.   Here are the goals build it cheap, with readily available pieces some of you may have laying around the house and reliable, simple to maintain, with a clean fit and finish.  I'm gonna start on it this saturday when I have some time to devote to it out in the shop. I'll have a parts list, and price list for what I have into it.  Once I'm done with the filter, I'll put it into action with a bait tank build out of a 55gal plastic barrel.   

[pdolewa]

Perfect I am actually looking to make my own filter

[FRESHBAIT]

Ok,  so I've gotten around to fooling with this gravity filter.   I'll be using a 5 gal bucket,  a couple packs of the the plastic scrubbies that you can find at the dollar store for the bio media,  I'm stealing the stuffing out of one of the wifes many throw pillows  for the fine filter material, and I'm taking one of my old HVAC blue filters and washing it and gonna use it for my coarse filter material,  for the plumbing of the filter I'll be using 3/4"PVC for the water coming in, and 1-1/4" for the water going out.   I went bigger for the outflow b/c the incoming water is under pressure,  the outflow will just be gravity fed  so I want to make sure that my outflow will handle the water coming into the filter and be able to get rid of it at a fast enough rate.  Some asst 90 deg elbows, some couplers should cover the plumbing portion of the piping. 

I have a couple ways to go about setting up this filter to work with a bait tank.   I could run the pump into the filter which would be above the tank and have it drain into the tank. 

Or I could mount the filter slightly above the tank and next to it so that the drain will siphon back into the bait tank.   The pump will pump water into the filter and the drain will allow the water levels to  equalize b/w the filter and the tank.  this would maintain water in the filter. 

I'll be setting it up to be used either way, so I'll show how to hook it up to run as a siphoning drain as well.   

Now off to the shop to start taking pictures and I'll post them later tonight.   

[Kevin23]

The best way to do it is to mount your filter about a foot above your tank and just let gravity do its job. You will want to put in a valve on the exit so you can control the outflow allowing your filter to maintain water above your filter media at all times. They are only a couple bucks for a cheap plastic one.. its all you need.

Its pretty straight forward on how to do it. Water entering a bucket up top, fine media, course media, bio media, exit on bottom. You might need a brick to put on top so the filter media doesnt float up too high. Go ahead and put in an overflow as well in case your filter ever gets backed up. The overflow is a 2" PVC outlet angled down out of the bucket towards your tank. No valve, just a straight shoot so any water backing up can go out into your tank instead of overflowing.

[FRESHBAIT]

I'm well versed in the making of Gravity filters,  However some of our fellow members may not be. That is the point of this DIY.  To show step by step how to make one, as well as a few variations.

I have finished the filter and taken the pictures, I just have to upload them. 

[FRESHBAIT]

Here are some of the parts we'll be working with


As you can see just a run of the mill 5gal bucket, a snap on style lid,  6 packs of the plastic dollar store scrubbies,  3/4"PVC, 1-1/4" PVC,  90deg elbows, some screw type couplers and some t-fittings


Cheap dollar store scrubbies,  I've been using these for years in differant types of filters that call for Bio media.  They have a ton of surface area for the good bacteria to colonize.  Another bonus is that they are cheap, 


What I did next is determine where I wanted my inlet and outlet for water flow.   I know most people will just go and drill holes in the bottom of their buckets and suspend them over their tank which is fine if you have that option.  I always like to put mine up on a shelf slightly above the tank,   So what I do is drill a 3/4" hole for my threaded coupler for my inlet from the pond pump.  I still have to put the spray bar on.  Next I drilled a hole to put my 1-1/4" threaded coupler  through, this is going to be used for the outlet.  I placed it up above the bottom of the bucket b/c I'll be putting on a 90 elbow and a short length of PVC towards the bottom of the Bucket.  This will allow for my bio media to be covered in water at all times and allow the water to be drawn down through the bio media and out though the oulet/drain tube.   Just remember to put some fish safe silicone around the inside rim of your through fittings so it will squeeze out once you tighten it down making a gasket seal so you don't have any unwanted leaks


To see how much bio media I have, I put in the scrubbies, looks like it'll be pretty good.  About 2.5"-3" of bio media.  You could use store bought bio balls, I saw some at the pond store the other day and they wanted around $15 for a pack of 15 or so bio balls the size of a golf ball.   I spent $6 on 36plastic scrubbies at the dollar store that'll do the same thing.  Or your could put cutup pieces of pvc pipe, or take a bunch of plastic banding material that the lumber yard throws away and stuff it all in the bottom of the bucket.  You just want to give the bacteria a place to colonize, and they'll colonize on pretty much anything.





tomorrow I'll be showing the making of the internal spray bar, and drain tube.   Which will then be followed by the fine filter material and coarse filter material. 







     

[FRESHBAIT]

Ok,  now for some more pictures of the DIY gravity filter

The spray bar.
I typically use just a single spray bar you could get really fancy here, heating up your PVC into any shape you want to, but I'm going simple on this one.
I used some silicon and made a bead around the lip of my fitting that is getting inserted through the hole I drilled in the side of the bucket.  I ran a bead on both sides of the fittings where it will mate up against the bucket.  I also put thread tape on just to make sure I wouldn't have any leaks.  I then glued in a short section of 3/4" pvc to get my 90 deg elbow out from the side of the bucket.




I then put my 90deg elbow on and angled it off to the side just slightly, this is where a game plan comes in handy b/c if your off with your distance then you'll run into your outlet pipe. I would recomend putting your outlet pipe in first then do your spray bar.   I didn't do it that way b/c I thought I had some 1-1/4" threaded adapters in the shop but I didn't so I just kinda winged it as I did it.


I just held up a 1-1/4" 90deg elbow to check my clearance, it's snug.  But it'll fit.  One thing I'll be changins is the angle of the inlet connection so that it's parallel with the outlet. Its just more asthetically apealing to my eye, and it'll work with the bait tank that I'll be doing for a DIY.


I then cut another short piece of 3/4"pvc for another threaded adapter,  the threaded adapter is what your hose fitting is gonna screw into.



For the spray bar itself I just took some 3/4" PVC and eyeballed it up against the bucket,  I wanted it to be a fairly snug fit.  On one end is a end cap glued on,  I don't glue the spray bar into the female threaded adapter b/c it'll allow you to pull out the spray bar if it clogs up, and also allows for cleaning the filter material.





For the holes in the spray bar,  you can drill a bunch of holes along the bar, and you can angle them to spray water over your entire filter material.  I just used my angle grinder and cut slots along the pipe in a pattern which I felt would give me the best coverage.  I cut into the pipe just enough to make a hole. 



Now for my outlet pipe.   I used 1-1/4" pvc b/c I wanted to ensure that my outlet would be able to handle the incoming water with out overflowing my filter.  I just measured with my calibrated eyeball the height I needed and glued my riser pipe to my 90deg elbow,  Which will allow me about 1.5" up off the bottom of the bucket. Keeping it up that high will keep the outflow riser pipe from sucking up the goo at the bottom of the bucket and dumping it back into the tank.  I then eyeballed another section of PVC pipe so that my riser pipe would fall in the middle of the bucket.  I glued it to the 90deg elbow, but did not glue it to the female threaded adapter that goes through the side of the bucket because itll allow me to pull the wafers of filter material out of the bucket. 



Tomorrow I'll show the filter material (wafers) that I cut up from synthetic blue plastic aircondition filter,  and some pollyfill snow blanket I took from the wifes holiday decorations she put in the house.  I'll also post up the final parts/price list if you were to build it from scratch.  This project won't be finished until it's hooked up to a bait tank and running, so once this filter is finished being assembled I'll be rolling right into a DIY bait tank build out of a plastic 55 gal barrel that if you look on craigslist can be had from $5-$35.  Sit back and enjoy the pictures and maybe get inspired to build one of your own. 

[skybuster20ga]

great thread! i have mine up and running and working great so far.....i dont have the spray bar i made dropping on the filter. instead i have it just running out a 3/4 spicket....is the spray bar necessary for anything other then distributing the sludge/dirty water more evenly over the fine/coarse filters??

[FRESHBAIT]

Just wanted to tell everyone to keep Senior Chief Boatswainsmate Terrell Horne III.    family in all your thoughts and prayers.  He was killed in the line of duty Dec 2nd off the coast of California.  Santa Cruz island he was part of a USCG boarding team who was attempting to stop a drug smuggling vsl, which turned and rammed his USCG small boat.  He gave his life  by pulling his coxswain out of the path of the collision strike area.


I'll finish up this thread tomorrow once I get back from work.

The spray bar helps spread out the water over the filter material,  it also will help aerate the water some to if your water is that high in the filter. 

[FRESHBAIT]

Ok here we go the final part of this DIY gravity filter.  Hopefully some of you are making your own. 



Ok Lets finish up the Outlet/overflow pipe.   its made from 1-1/4" pvc a 90 deg elbo,  1-1/4 female and male threaded coupler that goes throught the side of the bucket. 

overflow/outlet pipe assembled,  the 90deg elbow is glued to the outlet pipe.   


the Female and male threaded coupler is screwed together and is sealed like before with thread tape, and a bead of silicone to keep it from leaking.  The outlet pipe on the inside of the bucket will just insert into the coupler.  I don't glue it in b/c I want to be able to take it out so that I can get my filter material out to get it rinsed off.  On the outside of the bucket the PVC pipe is glued into the coupler.




Your outlet pipe needs to be set just about 1/4" off the bottom of the bucket this will allow the water to flow up and out of the out let pipe.  One thing to keep in mind is if you run your tank/filter for a long time you could possibly fill the bottom of the bucket up with sludge and it could possibly either clog up that area of the filter or even pass up and out the outlet pipe. You also want to make sure that its centered in the bucket.   



Next I put the 6 packs of dollar store scrubbies into the bottom of the bucket. 


Next I need to cut my Filter material. 
I use two types of filter material a coarse material to catch all the large debris,  the fine material will catch all the finer material.
the Coarse material is just blue synthetic air conditioner filter I just took out mine from my AC washed it and just bought a new one for the AC for the House.  New it'll run you about $6 at Lowes. 


I then use the 5 gal bucket lid to give me and Idea of my size and I take a large pair of tin scissors to cut out around the blue filter material, I then cut a round hole in the middle for the outlet pipe to fit down through.




I cut out two wafers and stacked them on top of each other, this will give me about 2" of coarse filter material.


Next I need to get my fine filter material cut, this is just 16oz  polyfill type material.  What I grabbed was in the wifes christmas decoration tote out in the garage.  I figured that if she hasn't put it out with the rest of the decorations yet then I can use some of it.  A pack like this can be bought up to some place like wal-mart for around $5 and you'll have a ton left over, or just take a few pieces from the christmas decorations like I did.  I like the mat/blanket type material b/c it tends hold together better and come out of the filter better for cleaning.


unfolded out of the package



doubling it up to cut it to shape


Like before I'm using the bucket lid to give me my shape. 


Once cut into shape I then cut an X in the middle so that it'll fit snug around the outlet pipe and allow it to pass through the middle.



I doubled up on the fine material and fluffed it up a little bit to give me about 2" of filter material, 


Once your coarse and fine filter materials are cut to shape, you'll want to stack them so that the fine material is on the bottom and the coarse material is on the top



Now for the final assembly of the filter. Your scrubbles are in the bottom of the bucket


Then your gonna want to put your filter stack into the bucket,  fine material will go on top of the scrubbies, then the coarse material on top of the fine material.


Once your filter stack is put into the bucket and tucked up under the female threaded coupler, You insert your outlet pipe, a little downward pressure and wiggling to make sure you don't get any scrubbies stuck under the outlet pipe.


Once inserted you just slide it into the female threaded coupler.  It should still be centered into the middle of the bucket.


Next your gonna want to reinsert your spray bar.  I made it so that it was removable, and that it would be a good snug fit in the bucket.





Make sure the spray bar holes are pointing down towards your filter material,  you don't want it spraying up into your lid, as it could cause it to leak. 

The outlet going back into the tank,  I use just a T fitting b/c then I don't have to worry about it getting clogged up, and it seems that the T fitting tends to areate the water pretty good.  I currently just have this kinda mocked up, as I plan on doing a DIY Bait tank following this thread out of a 55gal plastic barrel. 

[FRESHBAIT]

5gal bucket. With lid  2.97
Coarse blue filter 5.97
Fine filter poly fill 3.98
PVC pipe fittings 3.20
PVC pipe if you don't have any laying around you can pick up a couple 2' pieces at the store for around $5 most small hardware stores sell it by the foot
Six packs of dollar store scrubbers $6

Total cost if you dont have some of the parts laying around from other projects is roughly $26 and should handle hundreds of bait . You'll also need a pond pump I just picked up a 500gph pump for $22 online

[brl]

Thanks for doing this freshbait!

[FRESHBAIT]

Hopefully my thread here has enough information regarding the build up of this style filter and hopefully there were enough pictures..  if anyone had questions regarding any portion of the build up feel free to ask.   Or of you,d like to see something in more detail.

[jethro]

Freshbait, you are my mentor here on this bait tank build. Might have to stop by and visit when I go to visit my pop in Boothbay for X-mas.

I think you have answered all my questions on the filter itself. You said you will use a 500gph pond pump in this build that you found online... is it submersible? I'm finding pond pumps at home depot, but they are all submersible. Is that what I want? And if so, does it just go in the tank like it is or do I want to build a box around it? Pretty clear on the tank, the filter, all the filter media... just not the pump.

This one says 1000gph... is it going to matter? You recommended an 800gph pump in my build thread. It's magnetic drive, will that work?
http://www.lowes.com/pd_216243-70161-19037_4294822939__?productId=3024810&Ns=p_product_avg_rating|1&pl=1&currentURL=%3FNs%3Dp_product_avg_rating%7C1&facetInfo=

[FRESHBAIT]

You can either go submersible or plumb it from the tank into the pump then to the filter.   With the pump submerged you will get some heat so it can be a good to keep the tank from freezing.   With a strong pump you may have to make a screen guard around it to keep your smaller bait from getting sucked up into the pump and clogging the impeller.   That 1000gph. Pump will be fine, the mag drives last longer and run quieter.   If your gonna want to really stock your tank your gonna want  really good turnover through your filter.   100gal tank with 1000gph pump will filter all your water 10x an hour.  Which is a lot, but with high fish densities I think it's perfect.   The 1000gph rating is at no head so the higher the pump has to pump the water up its output  decreases untill it reaches a point it can't pump the water any higher.   Plus with a spray bar, fittings, and size of piping./tubing it decreases outlet flow Uteit as well. 

[jethro]

Yeah, with 100 gallons, I can't imagine it will heat the water up too much. My garage is totally unheated and not insulated, so it's gonna get cold in there.

[HardwaterFish]

Great thread. Thanks freshbait

[jethro]

Can I use regular PVC pipe cement to fasten the PVC together? That purple stuff with the primer is pretty stinky.

[FRESHBAIT]

Use what ever PVC cement you want,  that's what I had in the shop so I used it. 

[jethro]

Can I use stainless steel hose clamps in the tank itself? Or is there a plastic option? Was thinking maybe just using heavy duty zip ties too, but don't want the chance of failure.

[FRESHBAIT]

I use stainless steel hose clamps with no problems.   I one did all all my plumbing in PVC, but didn't like it as it made it a pain at the end of the season when I break every thing down.

[StingingLips]

awesome thread man, I will need to make one of these for my set up next year for sure.

[jethro]

Little confused on the output pipe... is it's fitting going to be above the water level, since I am elbowing down to the bottom of the bucket? Is this fiter going to be something I have to prime to get the gravity to do it's work? Just wondering how critical it is to have these fittings through the bucket 100% watertight.

[FRESHBAIT]

Fitting should be water tight going through bucket.  Other wise it'll leak and make a wet mess every where.   Purpose of elbow and pipe going to bottom is to draw the water from the bottom of bucket.  That way it passes through filter material and bio material.  Bucket should have water in it at all times what will happen is. Water will be pumped in and will fill bucket once it reaches level of outlet fitting it will start to drain by its self.  Water will be drawn through media and draw up through outlet pipe.   One area of concern I rate of flow out the out let pipe, that's why it's significantly larger than the inlet.  The inlet is under pressure and therefor flow is higher.  To account for that is to use a larger pipe that can flow more water.  If your outlet can't handle the flow of water coming in then your filter can over flow.  And you need to put in another through fitting just for an emergency overflow.  To keep from having to do that extra step just put in a larger outlet pipe. Does that answer it doctor gee?

[jethro]

Yessir, answers it perfectly. Actually, while waiting for an answer I just powered it up. See my thread for pictures and please give feedback!

[FRESHBAIT]

Ok I'm goin there next

[FRESHBAIT]

The bio media doesn't have to be submerged.  It just needs to be wet in an oxygen rich environment.  Hence why you see some of the newer wet dry sumps out there. The way I understand the concept of the gravity filter, by having water level just at your coarse media your agitating the surface if the water, helping to create a oxygen rich environment. 

 All gaseous exchange happens at the surface of the water,  carbon dioxide exits the surface,  oxygen dissolves into the water.  Air stone just help turn over the water to keep it circulating in the tank,  there may be some gaseous exchange at the surface of the bubbles produced, but I'm not sure.  They also help introduce fresher air into tanks/aquariums with tight fitting lids.  Helps get rid of stale/stagnate air.  Air Stones/bars just look aesthetically pleasing to the eye.

The large stackable plastic filling cabinets are a way to increase your bio media.  Especially for large tanks.   

[jethro]

So, just a little something I would like to pass on... and maybe if I really scoured FRESHBAIT's post here I would see it, but I learned the hard way... when building everything after a mockup, remember that you don't want to permanently fasten the fittings right at the bucket (filter). I glued everything together except the hardware actually in the filter, but you want the ability to be able to wash out your filter and be able to move it. Don't glue all the pipes right into the thing! I'll be cutting off my ball valves when the time comes.

[Dispy]

So, just a little something I would like to pass on... and maybe if I really scoured FRESHBAIT's post here I would see it, but I learned the hard way... when building everything after a mockup, remember that you don't want to permanently fasten the fittings right at the bucket (filter). I glued everything together except the hardware actually in the filter, but you want the ability to be able to wash out your filter and be able to move it. Don't glue all the pipes right into the thing! I'll be cutting off my ball valves when the time comes.

PVC Unions will correct that issue.

[jethro]

PVC Unions will correct that issue.

Ah, perfect solution.