View Full Version : ok to back-flush Platypus filter with syringe?

ATL Backpacker
06-22-2015, 10:52
I've got a 4L gravity filter from Platypus. It's about 5 years old. I filter about 50 gallons/year but haven't good about regular back-flushing of the filter. I have a syringe from my Sawyer mini. Can I use that to backflush the Platypus filter? And if so, better to backflush gently or go ahead and give it a good spray thru?


06-22-2015, 11:57
I thought you were meant to back flush it with gravity? As in hold the clean bag above the dirty for a couple of seconds?

06-22-2015, 11:58
Not sure if the syringe will work, but according to the Sawyer website you should give it a good hard spray through to prevent any paths of least resistance.

ATL Backpacker
06-22-2015, 20:17
I thought you were meant to back flush it with gravity? As in hold the clean bag above the dirty for a couple of seconds?

yes that is what Platypus says to do. But my filter is so slow (assumedly particle-filled as I haven't been good about flushing), that I thought a syringe would give me a quicker and more thorough cleansing. The sawyer syringe fits nicely over the platypus filter.

Just Bill
06-22-2015, 22:57
I believe the Platy is just a paper pleat style filter- totally different than a sawyer and likely not meant for a backflush under pressure.

Unless it's dry and in the bag never used- I wouldn't trust a filter that's been sitting 5 years.

One thing you can do to help a gravity filter in general-
Flip the hoses. If you have the long hose coming from the dirty bag, with the filter attached to the clean bag via the shorter hose, you will generate more head (pressure) and speed up the filter. Head is simply the distance from source to outlet. The platy was always rigged a little dumb. With the filter only a foot away from the filter bag you can only generate one foot of head (1/2 psi) no matter how high you hang the bag.

So if you flip the hoses, or get new hose, you can hang the bag as high as you can reach and greatly increase the head pressure at the filter itself.

Sawyer, platy, or any gravity system- sometimes you need to suck the outlet a bit to get it going. Not exactly a siphon effect but sometimes there is some trapped air in there that messes things up since it's a "sealed" system. Sometimes just cracking the cap on the lower bag will get it going... and make sure there isn't trapped air in the lower bladder.

06-28-2015, 09:11
Given the type of filter this system uses.....Does anyone treat their water after filtering for viruses and such? If so, with what?