waste tank 1998 405

[nickhajdukovic]

I own a 1998 405 Carver aft cabin. It has a waste smell coming from the front holding tank area. I have replaced all the lines and also pressure tested the tank and there are no leaks. As far as i can tell the odour is permeating from the tank. Has anyone heard of this happening?
Also, does anyone have experience replaceing one of these tanks. There does not seem to be enough room to remove it. It is under the dinette seating on the port side.
Thanks

[AaHubb]

Before you try removing the tank try this simple test. Use a clean rag to wipe down the surface of the tank then give the rag a sniff test. If the oder is strong you have most likely found your problem, other wise keep searching.

[waybomb]

The dreaded sniff test!

[nickhajdukovic]

Thanks guys, sounds like a pretty logical test, i will give that a try and let you know.

[MissWhit's]

I have a 2001 406 (same vessel) with the same problem. I took the boat to the marina and had them pump it out as best as they could. I then took the boat back to my slip and removed the tank level switch assembly and wet vacuumed out the rest. I performed a high pressure spray (Water hose with nozzle) inside the tank thropugh the same float level access hole and performed this until the BOTTOM of the tank was clean. Problem is with these tanks the suckout feedthru is about 1 inch above the bottom of the tank and hard sediment accumulates. After I cleaned the tank using the earlier method I filled the tank up with water, Calgon water softener, clothes washing detergent and bleach. I let this sit in the tank for 5 days then had it sucked out. I add two gallons of water, Calgon water softener and clothes detergent after every pump out. My boat no longer smells like the town sewer plant while driving by. Do a internet search about the chemicals and how much to add. Many topics on this.

John

[nickhajdukovic]

I was thinking about cleaning the inside of the tank. Now i will for sure but it will have to wait untill the spring as we have just put her away for the winter. Thanks John