Ss Water Tanks And Chlorine Don't Mix

[jonniebkk]

Well, in an effort to self-purify my local Pattaya water supply, I bought some chlorine tabs to put in my SS water holding tank. These are the kind sold at pool shops and are about the size of a hockey puck. Anyway, I popped in in and it settled on the bottom. When I drained and cleaned the tank recently, I noticed there was rust around the area where the chlorine puck had settled. When I displaced the puck a pin-hole leak sprank from the bottom of the tank where the puck had been. Apparently, the chlorine puck had eaten a hole in the bottom of the tank. It is just a pinhole sized hole for now.

My question now is can I save this tank by having such a small hole repaired or must I buy a whole new tank.

In future, I guess it would be better to suspend the chlorine puck in some type of container in the water so that it does not directly contact the SS metal of the tank. I think the fact that the puck just sat on the bottom at the same place for so long (couple months) is what caused the hole.

[chownah]

If you are lucky the pinhole will be just that, a tiny hole through the tank and there will not be a general failure of a larger area of the tank. If it is just a pinhole in an otherwise sound tank you can simply install a sheetmetal screw backed with a rubber washer to seal the hole....either from the inside or the outside. Best to try to use a stainless steel sheet metal screw so as to minimize the possibility of galvanic action enlarging the hole.

[jonniebkk]

Thanks for the advice...now where to find such a screw in Pattaya. It sure beat my neighbor's suggestion of plugging it up with some gum

[PhilHarries]

Sounds like you created a zone of very high chlorine concentration between the puck anf the tank shell that caused the corrosion and ultimate failure. Can you get into the tank to do a close inspection of the areas? There maybe only one pinhole but there may be several other pits close to breakthrough. A self tapping screw would work but there may not be enough material thickness in the immediate area around the hole to get the threads to purchase and grip for a leak tight seal. You may find it better to use a stainless steel bolt and nut with two large washers one either side and pack silicone sealant under them however you will have to get access inside and outside the tank for this repair. There is still the problem of sourcing the hardware but I would have thought any builders merchants that stock stainless steel bathroom fittings would have them. Sorry can't come up with specific names as I don't live in Pattaya right now and never had to do this kind of domestic repair work in Thailand.

[chownah]

If you can't find stainless steel screws and if it is possible to get to both sides of the hole then using a bolt/washer/nut of any type of metal will work if you drill a hole slightly oversized and put a plastic or rubber sleeve around the shaft of the bolt and plastic or rubber washers under the bolt head and under the steel washer on the nut end....this way the bolt/washer/nut assembly will be completely isolated from the tank.

Picture hanging plastic toggle screws or plastic lag screw inserts might allow this approach to be done from one side only.

Also, gum isn't a bad idea as long as it is epoxy gum.....hey, I'll bet silicone sealer would work too....and if the area under the chlorine puck is generally eroded you could but a coat of silicone sealer over all of it to stop further corrosion....I guess. I had a water pump with a screw on top which you removed to prime the pump....I lost it....I whittled a piece of wood about he right size and screwed it in....it held ok and I figured I would go buy a replacement screw....but I forgot....it lasted for two years and then the pump burned up which had nothing to do with the wood plug.

Chownah

[jonniebkk]

Good suggestions all...if I can find a tiny Thai boy could gain access through the top...it's a 1400 litre SS holding tank with the standard size pop-up round lid on top. Might try the silicone solutions first...seem the easiest and it is a tiny tiny hole for now.