Alex,

I have substituted a 10 (or 10 1/2) stopper and airlock for the
original airlock without a problem. However, the bottom of the
stopper does dip a bit into the wine. You may want to try a 11
stopper as it should elimitate the amount that touches the wine.
Also, the lid submerges a bit when you pump up the tube, so you may
get a bit of wine in the airlock when initially sealing the tank.
There are two ways around this: (1) Put the stopper in the hole after
pumping the tube, or (2) raise the lid slightly before pumping up the
tube. For you situation, #1 might be best as you don't run the risk
of having any headspace.

I think the diameter of the 300L tank valve opening is 3/4" female
NPT. I'm not too familiar with 3A sanitary vs non-sanitary
properties, but make sure you get male threading to fit into the tank.
You can use a hex nipple that is male threaded on both sides if your
valve only has female threads.

David
Denver, CO USA

"Alex" > wrote in message >...
> Hello,
> I just bought a used 300L Marchisio tank. The tank is missing the
> airlock and the spigot. I noticed that St Pats sells this brand of tank and
> replacement airlocks and upgraded ball valves instead of the spigot. So can
> I use a regular stopper and airlock in the lid or is the metal too thin for
> a stopper to stay put? The replacement airlock is only ~$10 but I would
> have to mail order it. Which is better the original type spigot the tank
> came with or a ball valve? I noticed the ball valves St Pats sells say that
> they are not A1 sanitary or something like that, does it matter? I would
> like to hear from anyone with experience with these tanks.
> -Alex P