Peggy (or any one else or would like to coment) I am looking at purchasing a boat that has a fresh water tank that has be unused for a very long time, long enough to build up a slim that cloged the water strainer(screen) after testing and running appx 25 gallons of water so that it noticable reduce water and pressure.The water has a noticable foul oder. My question is this,can I salvage this tank by a clorox treatment and draining (into the bilge not plumbing system) two or three times if needed or do I just bite the bullet and replace the tank ? As info the tank is plastic (poly) appx 50 gallons and 5 years old.We do not drink the water but do shower and do dishes with it.I am guessing the tank has sat 6 months with water in that was not treated or used.I'm thinking there is a slime inside it, as there was a slime inside the heads (it washed away with just a couple of flushes)The slime was black it that makes a difference and washed off the strainer screen with a water hose easily.Thanks in advance for you thoughts and your help to all on this web site !
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rotten water
I would think clorinating your tank will do the trick. The black stuff is probably a type of mold or algea and the chlorine will kill it. To a full tank add about a quarter cup of javex or similar product and let set overnight and then flush. Do this a couple of times. This should almost dissolve the black stuff. If you tank has an aroma that's not chlorine your problem is greater than one I've encountered. Good luck.
I would think clorinating your tank will do the trick. The black stuff is probably a type of mold or algea and the chlorine will kill it. To a full tank add about a quarter cup of javex or similar product and let set overnight and then flush. Do this a couple of times. This should almost dissolve the black stuff. If you tank has an aroma that's not chlorine your problem is greater than one I've encountered. Good luck.
Sanitization ... when slime/bio-film is present
If you have a 'slime' or noticible biofilm (glycocalyx) in evidence, then simple 'sanitization methods' will not routinely clean such tankage very well, if at all. The typical 'sanitization' methods published for RVs and boats typically are only for uncontaminated or new tankage thats being put into service for the first time. The presence of a developed bio-film (MASSIVE MICRO-ORGANISM COLONY) takes you into more aggressive territory - for safety and hygiene. Since you have a 'plastic' tank the cleaning can be quite aggressive as the polyethylene is quite inert to such chemicals. If the tank has an inspection port / hand hole, etc. then the very best method is to get inside with a long handled brush and simply scrub with detergent, perform a high velocity flush with a hose, then follow with a sanitization. Disinfectancts such as Chlorine from Chlorox will only kill / stun the upper surface layer of a developed biofilm leaving the deeper layers to be quite alive and unaffected (and available to reinfect). If mechanical scrubbing is impossible, then up to TEN very aggressive repeated santizations with Chlorox, etc. may be needed to destroy the biofilm. Typically each such sanitization is followed by aggressive rinsing wherein a fast-as-possible water stream is used to mechanically remove the partly destroyed biofilm. For tanks without inspection ports sometimes the attachment of a soft copper pipe to the end of a garden hose will be OK as you will usually able to bend the soft copper enough to pass it though the normal filling nozzles on the tank ... Just hammer the end 'almost' flat so that the water leaves the pipe with high velocity. When sanitizing be sure that tank is totaly filled and doesnt have an air bubble on the inside top surfaces ... as the biofilm will also probably be on the inside top surface. Consumer grade Chlorox, etc. is typically a 5% solution of equivalent Chlorine. The typical sanitization strength ( 20 parts per million) for sanitization purposes for a 50 gallon tank would be approximtely 5-6+ fluid ounces of chlorox. Add the Cholorx fill the tank completely and Let soak for at approximately 1 hour, then force flush/rinse with water. Up to 10 separate/repeated sanitization/rinse cycles may be needed to totally destroy/remove the biofilm - if you cant get inside the tank to scrub it. If you had a chemistry background, and there were no rapacious lawyers on this planet, I'd recommend a caustic soak with sodium hydroxide to simply dissolve all the bioburden. Caustics are very dangerous and shouldnt be used unless you have the very specific knowledge of their precise usage. Or, if you live near a dairy farming area ... you can possibly hire a 'dairyman' to do this for you ... then sanitize. How do you know that the biofilm has been removed? simply swab/touch the tank walls with a finger, when the 'slime' is no longer noticible, then you can be quite sure that the biofilm is dead/removed .... then sanitize again one more time. Once the biofilm is totally removed, then you can sanitize with some confidence. If the biofilm is not removed, sanitization is of little use. If you want a brief detailed technical methodology of what the 'water quality' industry does, I can forward you some documentation. email: RhmpL33ATattDOTnet That industry now typically uses peracetic acid for sanitizations. Hope this helps.
If you have a 'slime' or noticible biofilm (glycocalyx) in evidence, then simple 'sanitization methods' will not routinely clean such tankage very well, if at all. The typical 'sanitization' methods published for RVs and boats typically are only for uncontaminated or new tankage thats being put into service for the first time. The presence of a developed bio-film (MASSIVE MICRO-ORGANISM COLONY) takes you into more aggressive territory - for safety and hygiene. Since you have a 'plastic' tank the cleaning can be quite aggressive as the polyethylene is quite inert to such chemicals. If the tank has an inspection port / hand hole, etc. then the very best method is to get inside with a long handled brush and simply scrub with detergent, perform a high velocity flush with a hose, then follow with a sanitization. Disinfectancts such as Chlorine from Chlorox will only kill / stun the upper surface layer of a developed biofilm leaving the deeper layers to be quite alive and unaffected (and available to reinfect). If mechanical scrubbing is impossible, then up to TEN very aggressive repeated santizations with Chlorox, etc. may be needed to destroy the biofilm. Typically each such sanitization is followed by aggressive rinsing wherein a fast-as-possible water stream is used to mechanically remove the partly destroyed biofilm. For tanks without inspection ports sometimes the attachment of a soft copper pipe to the end of a garden hose will be OK as you will usually able to bend the soft copper enough to pass it though the normal filling nozzles on the tank ... Just hammer the end 'almost' flat so that the water leaves the pipe with high velocity. When sanitizing be sure that tank is totaly filled and doesnt have an air bubble on the inside top surfaces ... as the biofilm will also probably be on the inside top surface. Consumer grade Chlorox, etc. is typically a 5% solution of equivalent Chlorine. The typical sanitization strength ( 20 parts per million) for sanitization purposes for a 50 gallon tank would be approximtely 5-6+ fluid ounces of chlorox. Add the Cholorx fill the tank completely and Let soak for at approximately 1 hour, then force flush/rinse with water. Up to 10 separate/repeated sanitization/rinse cycles may be needed to totally destroy/remove the biofilm - if you cant get inside the tank to scrub it. If you had a chemistry background, and there were no rapacious lawyers on this planet, I'd recommend a caustic soak with sodium hydroxide to simply dissolve all the bioburden. Caustics are very dangerous and shouldnt be used unless you have the very specific knowledge of their precise usage. Or, if you live near a dairy farming area ... you can possibly hire a 'dairyman' to do this for you ... then sanitize. How do you know that the biofilm has been removed? simply swab/touch the tank walls with a finger, when the 'slime' is no longer noticible, then you can be quite sure that the biofilm is dead/removed .... then sanitize again one more time. Once the biofilm is totally removed, then you can sanitize with some confidence. If the biofilm is not removed, sanitization is of little use. If you want a brief detailed technical methodology of what the 'water quality' industry does, I can forward you some documentation. email: RhmpL33ATattDOTnet That industry now typically uses peracetic acid for sanitizations. Hope this helps.
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