91 Accord Clutch Problem

My clutch pedal seems to be slowly sinking to the floor. Several times per week I need to refill the resevoir and bleed the system. I just installed a new master cylinder and slave cylinder. The problem has not gone away and I don't see any leaking going on. Very often the clutch pedal sinks toward the floor while I am driving. I discovered that I can get pressure back if I pull the clutch pedal back out with my foot and tap it several times. This will give me enough pressure in the line to shift for awhile. On a 15 minute drive I may have to do this 4 or 5 times. When I get out and look at the fluid level, it is usually down a little but no where near empty. Occassionally I will check the level and it will be almost dry. Obviously air is getting in the system. Is there any tricks to help me find the leak. I've heard mention of putting some sort of dye in the fluid to help spot the leak. If this is true where do I get such dye? Also is this a common problem that occurs even with a new master cylinder and slave cylinder? Any clues for the clueless would be appreciated. Thanks.

i had the same thing happen to mine but all i did was replace the master cylinder also. The problem has never came back. It rides smooth. I wonder if your clutch never catches gears then maybe its a bad master. You can buy the dye in parts stores but is not recommended for you to install it but a professional to.