I noticed a very slow leak coming from my drain valve. I just did a water change and it seems that there is a little bit of water coming out of the valve. I have tried tightening the cap but it seems that it might not be coming from the threaded cap. I noticed that the water that is leaking out is freezing around the valve. Any ideas ! I have had this happen before but when I tinker around with the valve it usually stops. I am afraid that it is going to back up into the tub itself and cause problems from freezing up inside. Is this something that I should be concerned with , or just let it be . It is a very , very slow leak. I have a Caldera Spa. Thanks !