Zipper sealing?

[Cehoffpauir]

Yesterday I seam-sealed my bivy tent, with good enough results the first time I hosed it down today (just a few spots I already suspected). I then zipped the door and window completely open, struggling with the zippers (the sealer all over them, perhaps); then zipped them tightly closed, smoothly. I hosed the tent down again, and when I looked inside there was a considerable amount of water on the floor underneath the zippered flap w/ zippered window. I got inside and my wife hosed the tent, and I could see the water saturating the zippers and running down to the tent floor--literally spraying through them. So for a fact the zippers leak the most. Hence my question--do zippers need to be sealed? If so, how? One could sew little flaps all along the zippers to protect them, or is there an easier way?

Let me add I used Kenyon Seam Sealer 3, "for synthetic coated recreational fabrics..." My tent is coated nylon/tafetta (they're the same, are they?).

Thanks much.

[Zuri]

I've worked for a manufacturer of outdoor gear for 5 years. There is no way, we've been able to design and quite frankly I've never seen, zipper sealant. We put flaps, as you suggested, to seal out the rain that does come through the zipper. Often though, not too much rain should come through your zipper. It may be easier to replace the zipper and then reinforce it with flaps. I recommend YKK. We've tried other brands; but, YKK really is top notch.

And yes, coated nylon/tafetta is a synthetic coated recreational fabric.

[Cehoffpauir]

Well, thanks Zuri. I'll likely sew broad silnylon sheet over the face of my tent, rather than my first idea of 15' of flaps. The tent isn't high-end so I may not replace the zippers themselves, but if I ever do, I'll reference your suggestion of YKK.
The tent face leans back about 45*, exposing the zippers completely. If they were vertical this problem might be minor. Oh well.
121 days and counting!