Holding Tank Vent Filter Woes

[RoyS]

I installed a Sealand Saniguard holding tank vent filter for the first time this spring. Despite the $100 cost, I was very pleased that the device did indeed stop all odors when the head was flushed. Unfortunately, the device stopped working last week. It was advertised as lasting a full season but in my case it did not. Anyone else experienced a shorter than full season life with their vent filter?

 

[Justin_NSA]

Holy crap! Excuse the pun. For $100 it should last a lot longer than a season! Maybe it's your diet
FWIW, Wal-mart sells them for $78. When you say stopped working, have odors returned or is it plugged up? It could be insects if the latter.

 

[Benny17441]

It is indeed advertised as lasting a whole season but I guess it would depend on the number of flushes. Was the boat used a lot this season? I you feel your usage was moderate or average you should call them up and report the product failure and perhaps they might be wise enough to send you a free replacement.

 

[Justin_NSA]

It is indeed advertised as lasting a whole season but I guess it would depend on the number of flushes. Was the boat used a lot this season? I you feel your usage was moderate or average you should call them up and report the product failure and perhaps they might be wise enough to send you a free replacement.

Good advice. if the receipt supports that it was installed this season, it would be hard to defend false advertising.

 

[Peggie Hall HeadMistress]

Vent line filters become toast immediately if they get wet...one of many reasons I don't recommend them at all, especially on sailboats. So if your holding tank spills out the vent or even runs into the vent line when the boat is heeled that side, that's likely the cause of early failure. That can also cause the charcoal to swell up and block the vent line, resulting in other far more serious problems.
Oxygen is the key to preventing odor out the vent. Because vent filters impede the free exchange of air with gasses, they actually help to create the very problem they're sold to solve! Some changes in the vent line and through-hull, along with the right tank product usually solves the problem. At the risk of being accused of some shameless promotion, my book, available from the sbo.com online store (see link in my signature) provides a lot of information about what causes holding tank odor and how to prevent it. Whether you buy it or not, I'll be glad to help you sort out the specifics needed for your boat. The fixes are fairly easy and won't cost you anywhere NEAR $100! Neither does my book!

 

[Benny17441]

Peggie has spoken, the explanation makes sense, the filter probably got wet but I would still call them up and see what they do. The product is made to be installed in the vent line and the vent line is susceptible to getting wet. Unless a specific disclaimer was issued, at $100 a pop the least they could do is send you a replacement. The possible consequence of a blockage in the vent line is indeed serious as it could lead to a very messy situation. Get Peggie's book, it will last more than one season.

 

[bobtigar]

I can show you how to build one for less than $10.00 using a few pieces of pvc and activated charcoal. When mine stops working, I take it apart and refill with more charcoal. Had the same one for 6 years. Charcoal costs $6-$7 and will refill it 3-4 times. Funny, Peggy (in an old quote) thought these thins would stop the vent from venting. Found the article published in Sept/2011 GOB. Its attached. Bob

 

[Chris & Lenore]

Big Orange sells a direct replacement for the Sealand and it's designed to take apart and recharge as required.
They sell recharge kits but all you need is a box of pellet type charcoal from the aquarium store.
Well made with a bypass valve and molded in brass anchors for the screws.
While it does suffer from the same problem if water (or worse) enters it, replacing the charcoal only takes 5 minutes and about 5 bucks.
While I did increase the vent hose size, use the recommended chemicals and empty the tank weekly - I still had the ocasional bad smell from the vent. Adding the filter to the mix kept everyone happy (hey, it's a compromise - like sailing).
Chris

 

[Peggie Hall HeadMistress]

Funny, Peggy (in an old quote) thought these thins would stop the vent from venting.

I haven't changed my mind about 'em. The SeaLand or any other vent filter can most definitely block the vent (which will most definitely stop the venting) if it gets wet. That not only makes 'em inadvisable on most sailboats, but also makes it impossible to backflush the vent line to prevent blockages. It costs almost nothing to modify the vent to create the aerobic environment in the tank needed to prevent odor from being generated and you only have to do it once.

 

[thinwater]

Using a nitrate-based chemical with it, I get about 3 years. If it gets wet, it's toast, so mount it high, provide a by-pass, and try not to overfill the tank. If you cannot do those things, it's not going to work for you. At 3 years the surface will begin to foul with sulfur from the reaction (you will notice white and yellow deposits).

I'm not certain the life has as much to do with flushes as time and chemical addition. Diurnal breathing, temperature, and full half tanks are the big movers. It's about H2S generation rates.

 

[RoyS]

Well thanks everyone for your responses. In my application the filter and vent hose are mounted such that even when heeled there should not be any water or sewage in the lines or filter, nevertheless, I will perform an autopsy shortly. As to our usage, my wife and I spent three weeks in Maine cruising and it worked perfectly as advertised. After returning, the boat was idle for a few weeks and then we took it out for the weekend and the problem was evident immediately. I am quite certain that we never overfilled the 25 gallon holding tank. We used no chemicals. The Sealand company did kindly offer to send a replacement of a different design. I do not know if the design was changed to improve the product or to prevent home refilling of the charcoal inside. Peggy, I will order your book, shamelessly promoted, or not. Autopsy report next week. Meanwhile, has anyone besides me had this early failure?

 

[Peggie Hall HeadMistress]

One of the reasons it may have worked perfectly in Maine is temperature...it's a lot cooler there and the water is downright cold! Bacteria are far less active as temps drop below 75 F, becoming increasingly sluggish in the 60s....and it's bacterial activity that breaks down organic matter, generating noxious gasses in an anaerobic conditions, CO2--which is odorless--in aerobic conditions. Boat hulls and whatever is in them below the waterline take their temperature off the water...so if your tank is below or even mostly below the waterline, it may not have generated enough odor to know whether the filter was working or not.

Btw...you said you don't use anything in the tank. That guarantees odor out the vent. Before you install the replacement filter, try using a product called Odorlos Odorlos *according to directions* You might find you don't need the filter after all. I couldn't find it in the sbo.com store...you'll find it in RV supply stores for a lot less than any marine store prices.

I appreciate your buying my book...I'm sure you'll find it useful, especially the section "Holding Tank Odor--Odor Out the Vent."