question on finishing

Hi all. I just got a Murphy cup and looking forward to using it, but I have a couple of questions on finishing my syrup. Before i was getting my sap close to finished on my evaporator and then finishing on a propane burner, testing with my hydrometer to get it finished. Well, when I was reading up on these murphy cups and floats, I came across a thread that a guy said he took his syrup past done, let it cool and them added water back into it to finish, it threw me for a loop. You can do this? That would make things so much easier for me. Also, with the Murphy float, you can check your syrup even if it's at room temp to see if it's done?

Thanks Jason

Drawing off heavy is ok to do if you want. It’s easier to add sweet or distilled water then to boil water off.
When I draw off it tends to be a bit high as well. My auto draw will open and then the temp spikes as it draws off. Sometimes 1-1.5 degrees then slowly goes down. After a couple draws I’ll use the dipper and take a sample in the Murphy cup. If it’s higher then 67 I’ll open valve and add a little sweet from the syrup pan and check again. Once it’s good it gets filtered and off to the bottler.
You can check any temperature syrup with the Murphy cup. The dial tells you where your hydrometer will float at 66.9 brix.
The Murphy float is the same. But it’s not a vessel for a hydrometer. It’s just a dial that you float in say your canner and gives you the same reading. You then either check with a separate hydrometer cup or float your hydrometer in the canner as well untill the two readings match.

I sometimes need to thin, but that is because I send proper density syrup to my finisher and let it set there until I've gotten enough to fill a barrel or even 2. I then heat it to about 205-210F to filter it, just before filtering I use my Murphy cup to verify the density. I then add pre-syrup off the evaporator or even sometimes permeate to bring the density down.
Adding water, sap, permeate or pre-syrup works fine, but it should not be your go to plan. If you always need to thin it means you boiled too long, using more fuel and along the way you have made darker syrup. I have customers who usually ask for dark, but if your customers prefer amber or golden, you may not get as much of the lighter grades.

Thanks for the replies. This helps a lot. I don't sell anything, this is just for my family and we prefer dark syrup as it is, so boiling a little past and thinning afterwards is fine with me. Seems like this will simplify things a lot for me.

Jason