RayPak RHP100 Heatpump (pool heater) has a leak - with picture

My 6 year old Raypak RHP100 Heat pump pool heater is leaking from a small clear-rubber tubing that comes off the water manifold. The tube goes to an open (drain?) fitting on the bottom of the housing. I don't know what would keep this from leaking all the time as it looks like there is nothing to prevent water from coming out this tube/opening. But it just started leaking recently, so something has gone wrong.

If anyone has experience with these heat pumps I could use some advise.
The tubing is not even shown on the parts breakdown (meaning I probably have to buy the whole manifold if I need a part).

here is what it looks like:
http://i921.photobucket.com/albums/a...ps676e4d9e.jpg

Just to update in case this benefits anyone else down the road ...
I found out that the two clear rubber hoses have copper "ends or inserts" where they go into the 2" water manifold. The purpose is to alert the owner of corrosive water that is eating away at the heat pump copper piping. So when/if the copper ends erode away water will go into the tubing and dump on the ground under the heat pump to alert the owner (to start saving money). Raypak says they don't use this detection method anymore and I can safely plug the drain hose. Of coarse the corrosive water that has eaten away the copper ends has also been eating the inside of the copper heat coil too - so a new heat pump (or replacement coil) is going to be needed at some point.

PS. My water is corrosive - it requires constant attention. With the Salt Cholrinator system I use I find my PH levels are always high. I have to add a 1/2 gallon of muratic acid once a week (to 15,000 gal water) to keep Ph around 7.5. Now I am seeing the results of not keeping on top of it.