Help with bottletop Filter

Hey guys, any advice/input would be greatly appreciated:

Been using syringe filters but obviously its a pain in the ass, well Ive been using a caulk gun but that still gets to a pain. So thought about getting some bottletops but wasn't sure which ones. Been reading and asking and finally decided on the Nalgene Nylon ones...bought 3 of them along with 3 glass flasks instead of the plastic. I cooked up some Deca with a 2/15 ratio and it filtered thru with no problem at all in a short amount of time. Following day, I made up some TestE with the same ratio and let it cool down and threw that into the tops and started to pump. It was going great and then at 50ml... deadspot clog. Heated the oil back up to see if that helped and still same thing, about 1 drop every 30-60secs. Checked the glass, top flask, plastic connection, hose for any cracks/leaks and there were none. Checked the gauge on the pump and it was steady at 15 (where the deca flowed) and I tried higher and tried lower...still nothing. Gave up for the day and tried again with the 3rd filter, same thing...50ml clogging. Had to push the last of the Test thru a syringe filter...blah. I put nothing but water in the top receiver just to check it and not ever water was going thru (put that into the plastic obviously).

Seeing if anyone has any idea on what could be the issue. I've been told that maybe the gear is dirty, which sounds logical but it went thru the PVDF with 100ml out of a single syringe filter and could likely have gotten more. Have also been told that the BB could be causing it..which I have no clue about. I put the BB in there to help thin it out, I know its not needed in Deca/TestE but just to help thin it out...but what about if I was filtering Tren which will need it? Maybe I should switch over to the Millipore PVDF Stericups? I kept seeing that Nylon was the way to go if I wasn't using EO (which I wont) so went with that. The deca flowed perfectly but the Test was a prick!

About to order a box of 12 of the Millipore Stericups but cant figure out which neck size and medlab doesnt list it. Seen some say all Millipore are 45mm but I see in their catalog where the 150ml has 45 and 33mm necks. Should I get the Millipore or retry wth the Nalgene?

Sorry for the novel...just trying to figure out what went wrong or anything....


New member
As per my PM as well, any chance it could be your test raws? Maybe do a small melt point test on a pan on the stove with a laser thermo to see a general idea of its purity


millipore and the neck size isnt that crucial since it is the suction that creates the seal with the receiver bottle, it isnt threaded on or anything. I use 33mm- 150ml wheaton receiver bottles. If your raws are reaally dirty you may need to prefilter with a coffee filter. You can remove the filter membrane from a used millipore and use coffee filter material and very quickly prefilter through it before final filtering through the new millipore. May help.
will certainly try this for sure. I bought a small box of the 45mm neck bottles because I had called MedLab and asked about the neck size and they said it was a 45mm neck hopefully they will fit correctly.But I get your point about the suction, but there were no leaks or anything allong that line. I had just a little in there and looked at it and yu could see the filter paper vibrate, hear it, etc.
But ust to make sure...tear out the filter paper, cut a same size of coffee filter paper, and then vacuum with that? or do you mean simply run the warm oil thru the paper with no vacuum?

thanks man!


you dont even have to cut the coffee filter, just set it in. Remove the membrane, set in coffee filter, use vaccuum but it will filter FAST. Just may help and thought it might be worth a shot. Good luck.