to dry hop successfully this is what i do
to get excellent results from dry hopping [you can if you wish to use a hop sack]
1st let your brew in primary to complete fermentation
when you have a hydrometer 2 readings the same over 2 days is suffice

tip if you have a camera take a shot you then can magnify the image to get a good reading
if you do not have a tap , open your fermenter carefully not to disturb the co2 layer too much and drop spin the hydrometer in your brew what i did prior to getting a refractometer
star san your lid area open up slightly pop in your sanitised hydrometer
you do not really want to be hovering over a open fermenter dropping crud dirt of your jumper hair etc getting into your fermenter
if you do have a tap take a sample and fill your trial jar
when you have that same reading
re rack to your secondary onto your intended dry hop variety


hops in beer syphoned onto it
remember to keep as covered as possible lid ajar whilst syphoning
Now when you have your secondary fermenter full of beer dry hops
lid it up put in your blow off tube bubbler or whatever you use leave the lid a jar what ever is you method
cool your fermentation fridge dry hop at 15C for 5 to 9 days
step over now bottling day
using leaf hops is fine
now using pellet hops can be a problem getting the beer out
so i have wrapped stainless steel mesh round my hop trap this way i can dry hop with massive amounts of hops
this is boiled and sanitised every use
i wait until at least 70 80% of the dry hops have fallen through the beer dropped
you do not need to syphon and really should not by mouth if you have a large enough syringe my one is 100ml ample big enough to get the syphon going
https://www.youtube.com/watch?v=VXqlWSYyJJA

then once your bottling bucket is full bottle away
or if your pressure barrelling kegging do that
an important point is if you syphon from the bucket not the fermenting buckets tap
[never used the taps on my fermenters to transfer think that all them plastic taps on fermenters are not really designed to flow freely without sucking in air through the tap handles]
with a syringe and purge if any air that is present then transferring to secondary or your [ bottling bucket which i leave for a further day prior bottling]
for further clearing
when i do it i have within the day a nice co2 layer on top as my blow off will be showing signs of a bubble or 2 now and then or if i depress the lid it will bubble
If your fermenting with an open fermenter no lid i cannot comment on that
a good co2 layer for me in a sealed fermenter with a blow off tube works well