How to recharge holding tank vent filter -- w/pics

Kenpcfl

New Member
TECHNICAL Contributor
Oct 29, 2006
21
At SRO, several members had talked about refilling their holding tank vent filters. I recently did mine, and it saved about $100 bucks. I had been buying the filter from the manufacturer, because the larger size is not usually stocked anywhere else. http://www.environmentalmarine.com/accessories.html

Here's how to do it yourself, step-by-step:

First, purchase your pvc (dwv) fittings for 2" pipe, primer & glue, and the carbon pellets (the pellets can be found at PetSmart for under $5 -900ml):

vent5.jpg


Then, cut the vent filter in half using a hack saw:

vent1.jpg


Empty the old pellets, and remove the sponge retainer pads by pushing them out from the ends. You can wash the pads and let them dry for reuse:

vent2.jpg


Remove 1" of the label (with a razor knife) where you will be gluing the new fittings on. Then install the fittings with the primer and glue. Let this cure before adding the new pellets:

vent3.jpg


Place the pads back into the ends and fill the two halves completely with new carbon pellets, and screw the two halves together using teflon tape:

vent4.jpg



Options: You could use a no-hub fitting instead of the glue-on fittings that I used (that's the rubber tube with clamps).

You could replace the 30 ppi foam retaining pads with new foam: PetSmart has 30 ppi filter pads of the same thickness that you could cut them out of. However, I found the existing foam to be fine.


You could even make the whole thing if you do not already use a vent filter. The pipe is 14" long. The only thing missing in the pics above is this retaining wire screen stuffed in the ends first:

vent6.jpg



-Ken
 
I think I will just buy a new one of these. With my luck I'll cut my self and get ecoli. :lol:
 
thunderbird1 said:
How often (really) do you need to replace or refill the filter?
Good question. Who knows....the experts say every year. After spending $100 last year changing the filter, I was just going to wait until I had deck odor before swapping it again. Now, for $5 I'll swap it out regularly.

I'll tell you this: the charcoal works --the foam pad on the tank side smelled nasty, and the foam pad on the outlet side smelled like a foam pad.

-Ken
 
Hi Ken.............glad to see our official SRO "Token Regal Owner" has found our board! Thank you for taking the time to document and illustrate the alternative to replacing the carbon filter. :thumbsup:

I will be doing the same to thing to my tank filter when the time comes.
 
We get a good two years out of a filter with a 6 month cruising season.
 
Thanks Ken, the pictures make this an easy project over winter. Now I don't feel like I have to wait until we get an odor problem to think I got my money's worth. :smt038
 
great $$$ saving post....I offer a couple of suggestions based on personal experience.

Before cutting your filter, verify how it's secured & if you'll have a length problem. By adding the male & female connectors you lengthen the filter a couple of inches. Also determine if the increased dia of the connectors will cause any clearance problems.

Also.....my foam filters were ruined thus I discarded. Following a fellow SRO's suggestin, I used the feet end of a pair of panty hose to bag my carbon within the tubes.

It's been over a yr with almost weekly use & no problems. We pump as soon as we notice the tank 1/2 full.
 
I took a look at my filter today and it will present some challenges to do it the way you show it Ken. The center of the tank is moulded to fit the filter so I can't cut the center. I probably could cut between the center and the end though and that's what I will check out. Here is a picture of mine. And I just noticed it's time to empty the tank too. :smt043
 

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Dave:

Doesn't have to be cut in the middle.....you can always cut the tube close to one of the ends....after...of course....you have the tank pumped....
 
Dave, .....What a neat system --I wish mine was as easy to get to as yours! Like osd9 says, you can certainly cut off center....or use a no-hub coupling.........or make your own completely from scratch.
Also, you could just make an extension tube out from the tank fitting to allow for more room.

Ken
 
Kenpcfl said:
Dave, .....What a neat system --I wish mine was as easy to get to as yours! Like osd9 says, you can certainly cut off center....or use a no-hub coupling.........or make your own completely from scratch.
Also, you could just make an extension tube out from the tank fitting to allow for more room.

Ken

Cutting off center probably makes the most sense in my case and that's what I'll probably do. I can cut the rear half and won't even have to shorten the housing so I will have a slightly longer and maybe longer lasting filter as a result too.
 
Ken
Thanks for the great idea.
As I just purchased this boat in August as a Bank Repo,
I have been going through all of the systems on the boat and recently made a note to replace this filter as it looks like it has been a while.
And a constant user of PVC Parts to make life easier I can now add one more to the list.
Add PVC Glue and Purple Cleaner to the box with the Duct Tape in it!!! :smt038
Dan
 
Someone asked how long to the filters last....? Someone said the experts recommend changing them annually.......Well, I figure the experts probably work for SeaLand and have a vested interest that annual filter change at about $100 per.

I'm also from the "I need to understand why" school of boating and I could not find any authority to describe a change interval in measurable terms, so I deduced that

1. if you keep the level of solids and liquid in the holding tank way below the exit point on the tank for the vent line so the filter stays dry, and,
2. if you pump out frequently and never leave measurable waste in the tank when you leave the boat for a while,

that there is no reason that the carbon filter will be "used up". So in about 1998, I set out to see if maintinaing my boat as described above will affect the life of the filter. I plan to replace (or now relaod, thanks to Ken) when I get some tank odor when we flush the head. Well, I'm about 9 years into my experiment now and I have yet to need to change filters.

What works for me, may not work for anyone else, and used boats bring with them unknown habits of previous owners, so pick your own methodology.
 
Hey Frank-

Are you trying to tell us your sh*t doesn't stink? :grin:
 
I dont smell anything either :smt043

seriously I apply the same easy method. If you get sloppy on the maintenance you will smell it sooner or later i'm sure. Additionally if you are also spending the big bucks on the (blue stuff) head treatment and "DEODERANT" why would there be any odor?
 

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