Choosing my first rebreather SF2 vs JJ

[GF99/99]

well its downright tiny as full sized CCRs go, only 2.2kg. Not a super critical issue in very warm waters but its terrible for <5C kinds of conditions

Yup 2.2kg is pretty sad. This is where the larger radial scrubber options like the JJ or the ingenious Revo rotating scrubber really shine

 

[rjack321]

Yup 2.2kg is pretty sad. This is where the larger radial scrubber options like the JJ or the ingenious Revo rotating scrubber really shine

If you're going to have a full sized CCR at least put a full sized scrubber in it 5.5lbs/2.5kg+

 

[Henry_LKW]

what's the typical scrubber duration for a 2.5kg sorb?

 

[stuartv]

what's the typical scrubber duration for a 2.5kg sorb?

Rule of thumb is 1 pound per hour. But, that varies GREATLY based on many factors, including diver workload, water temperature, and other things.

 

[Herje8990]

As I mentioned above much earlier the biggest problem and the No Go for me on the SF2 is the scrubber. The OP is specifically asking about deep wreck diving. This is basically what the JJ was designed for. Proper deep exploration diving. Yeah sorry the SF2 is not built for that. I like my life too much to be running a CE rated 135min scrubber way over. Ill stick to the JJ 4kg radial XRC scrubber (almost twice the size of the SF2 scrubber) on a 6-8hr deep deco dive.

I think scrubber ratings is one of the most overlooked things people do not take into account when buy a unit. And also during dive planning. What if you have an issue and over stay your bottom time and rack up alot more deco, our you need to do in water recompression, or your in a cave and get lost and now your 6hr dive turns into an 8hr dive, how confident are you in your scrubber???. Usually people are always looking at WOB, CL location, cool fancy features like He sensors, pressure transmitters, etc. But don't forget your life if most dependent on your scrubber. And sorry a 135min CE rating is pretty sad. It is also something that most SF2 instructor do not disclose or like to talk about.

Direct from the SF2 manual pg. 13. Also SF does not like to share the CE test results, you will see that JJ will share them no issue.

View attachment 850875

SF2 also has the option to upgrade to SFX to 3.5KG scrubber.
FYI, I measured it once and you can easily pack 2.7KG of sorb into SF2's original scrubber with no change to WOB.

"its the indian, not the arrow" let's be real, most of RB in the market are designed for deep exploration dives to 100M (at least it's their advertised rating for liability reasons).

 

[Henry_LKW]

SF2 also has the option to upgrade to SFX to 3.5KG scrubber.
FYI, I measured it once and you can easily pack 2.7KG of sorb into SF2's original scrubber with no change to WOB.

"its the indian, not the arrow" let's be real, most of RB in the market are designed for deep exploration dives to 100M (at least it's their advertised rating for liability reasons).

Hi I did heard of the SFX! Isn’t it a SCR? Unless you are referring to using the sfx body and the sf2 head?

 

[Herje8990]

Hi I did heard of the SFX! Isn’t it a SCR? Unless you are referring to using the sfx body and the sf2 head?

SFX
If you think you need bigger scrubber you can just get SFX scrubber, mid/lower carbon fiber tubes and CL.

 

[Herje8990]

what's the typical scrubber duration for a 2.5kg sorb?

I'll share some of my scrubber use; I keep track of mine every time. The water temp is around 25-30.

 

[GF99/99]

SF2 also has the option to upgrade to SFX to 3.5KG scrubber.
FYI, I measured it once and you can easily pack 2.7KG of sorb into SF2's original scrubber with no change to WOB.

"its the indian, not the arrow" let's be real, most of RB in the market are designed for deep exploration dives to 100M (at least it's their advertised rating for liability reasons).

Thats pretty standard for all rebreathers. Usually all of them you can get about 10% more in the scrubber then advertised.

Also lets be real most exploration diving now is going way beyond 100m or penetration length in overhead is getting crazy now, especially with the B/O rebreathers becoming popular.

More and more people are diving deeper, further (overhead) and alot longer nowadays. Might want to have a look at what units all the current guys and gals doing crazy deep, crazy long dives are using.

I'll share some of my scrubber use; I keep track of mine every time. The water temp is around 25-30.
View attachment 851813

As I said befor yeah if you want to over dive a 135min rated scrubber go for it and I am sure within reason it is safe, but... That is a calculated risk you have to take. I am not saying that you can not as we all know the CE test is unrealistic no human can actually maintain a the test parameters but it is still a standardized test that shows the true flow and scrubber effectiveness. And sorry the SF2 did very very poor.

Personally putting 322min on a 135min rated scrubber is not worth the risk to me. I like my life to much and want to continue diving and in the grand scheme of things ill pay the extra to change my scrubber out. To put things in perspective 322min/135min means your over diving your rating 2.39 times.

My JJ XRC scrubber rated for 6hr so if I did what your doing that would be like diving it for 14.31hr. yeah sorry not worth the risk.

 

[Herje8990]

Thats pretty standard for all rebreathers. Usually all of them you can get about 10% more in the scrubber then advertised.

Also lets be real most exploration diving now is going way beyond 100m or penetration length in overhead is getting crazy now, especially with the B/O rebreathers becoming popular.

More and more people are diving deeper, further (overhead) and alot longer nowadays. Might want to have a look at what units all the current guys and gals doing crazy deep, crazy long dives are using.




As I said befor yeah if you want to over dive a 135min rated scrubber go for it and I am sure within reason it is safe, but... That is a calculated risk you have to take. I am not saying that you can not as we all know the CE test is unrealistic no human can actually maintain a the test parameters but it is still a standardized test that shows the true flow and scrubber effectiveness. And sorry the SF2 did very very poor.

Personally putting 322min on a 135min rated scrubber is not worth the risk to me. I like my life to much and want to continue diving and in the grand scheme of things ill pay the extra to change my scrubber out. To put things in perspective 322min/135min means your over diving your rating 2.39 times.

My JJ XRC scrubber rated for 6hr so if I did what your doing that would be like diving it for 14.31hr. yeah sorry not worth the risk.

I was doing some research on the XRC since i do some point plan on trying the JJ. Is the 6 hour rating on XRC CE rated? Or is the calculation based on scrubber size?

And where did you find the SF2 CE rating at 135min? The manual says no more then 3 hours/180min