Aloha Joe
Contributor
I’ve had the Geo 2 for about 60 dives and now have a few dives on a Perdix, so I thought I’d post my thoughts/observations. I’m sure some of this can change with time but I thought this could help someone on the fence about buying either computer, or upgrading or whatever.
The Geo 2 does pretty much everything I need it to for rec diving. In good light the screen is very easy to read and the numbers actually seem bigger and more legible to my 40 year old tiring eyes. That being said, I can see the big numbers but can’t read any of the subscripts. I always wanted the Perdix since I first picked one up and seemingly knew how to do everything I needed to with it, without ever seeing a manual. The Geo 2 is a different experience, where I have a bunch of dives on it and am still learning how it works just for rec diving. I felt weird about spending $1000 on a dive computer when I had 10-15 dives under my belt so I bought the Geo to get started with AOW and a couple of specialties.
There are a few things that made me splurge for the Perdix. At the moment it’s hard to say it was worth $1000 but I think I’ll feel better about the purchase with time. The Geo is tough to read in low-light situations - the backlight is just OK, requires a button press, and only stays on for 10 seconds max. I have a few night dives under my belt (starting the Night dive specialty this weekend) and I don’t like my computer being invisible without having to push a button. A few other things that have been bugging me are the alarms: 1) P02 has an alarm setting, but gives a WARNING that you can’t change/disable at 0.2 before your setting. 2) The Tissue Loading Bar Graph (TLBG) is pretty low resolution, and fills to it’s rec limit while I still have upwards of 20 minutes of NDL time remaining. So I’ve been feeling kind of blind to my actual tissue loading/limits, and don’t like being WARNED (blinking lights, beeping, flashing screen) about P02 when I’m well within my dive plan. Last, the Geo is decent looking but too big and bulky to be a daytime watch, and an actual watch strap pretty much sucks for donning over a wetsuit. Last, I wanted to check firmware to see if any of this has been updated. The manual says you don’t need to send the computer in, but you need a $100 cable. I don’t want to spend another $100 on the Geo. I’d like to be able to download my logs but for some reason the whole Geo package doesn’t seem worth the cost.
The Geo does a good job at what it does - there’s a reason it’s highly recommended for a relatively inexpensive dive computer. I feel safe and comfortable with it, and could tune in an algorithm that suits me the best for daily diving.
The other thing that made me get the Perdix is having everything in one place: for night dives, it’s nice to have gas pressure, dive info, and compass all in one place and always lit up. I”m scheduled to have Rescue Diver and 4 more specialties completed in the next month, so I that helps justify the expense I guess.
I did my first dives with the Perdix. Honestly the first thing I thought was, “Wow, the Geo is actually easier to read underwater!) and that was kind of disappointing. The Geo’s numbers are bigger, and the Perdix suffers from glare on the screen when diving during the day in crystal clear water. The second thing I noticed is my Perdix went into Deco while I still had 10 minutes of NDL left on the Geo. Fortunately that could be changed in the settings. I was surprised at how significant the difference is between ‘medium’ and ‘low’ conservatism on the Perdix (rec mode). The Perdix rec mode is more conservative than DSAT and that can’t be changed - only in tec mode, which has a different set of features (no auto safety stop timer, for example).
About algorithm: I’ve been diving the Geo mostly on DSAT, but recently switched to PZ+. Mostly because it’s super disappointing to do a deep wreck dive with nitrox, and have the rest of the boat diving Suunto and ascending when I still have 15 minutes of NDL left. But also, I’m in my first year of diving and felt that a little conservatism isn’t a bad thing anyway. Moving the Perdix to Rec, Low Conservatism is quite similar to Geo PZ+ at depth. But this is for the first dive only! Perdix was giving me more NDL on second and third dives, both on Nitrox and air. I did max depths of 108 - 99 -65 for my 3 dives on Sunday. As I said, Perdix Med got deco’d on the first dive with 10-12min remaining on Geo 2. Then I switched conservatism and it reversed.
Oh: The Geo 2 can’t change algorithm for 24 hours once it starts monitoring nitrogen. So you can’t try the 2 different algorithms back-to-back, even on 2 diving days since it’s less than 24 hours since you got out of the water. I dove in Fiji for 2 weeks, and once I got wet I was locked into the algorithm I had set.
Here’s first dive NDL limits: Geo PZ+ vs Perdix Bühlmann Low Conservatism (45/95)
Depth / Geo2 Air / Perdix Air /Geo2 32% /Perdix 32%
50.) 65. 76. 117. 157
60.) 48. 51. 74. 87
70.) 35. 36. 54. 62
80.) 26. 27. 42. 45
90.) 19. 21. 33. 34
100.) 16. 17. 25. 26
110.) 12. 13. 20. 21
120.) 10. NA. 17. NA. Perdix and I both know better.
130.) 8. NA. 14. NA.
Obviously the Perdix is something I can grow into. But honestly I thought about returning or selling it at first. Maybe one day I’ll consider tech (deco) diving and be thankful. Or maybe I’ll get used to having everything just where I need it on my wrist this weekend while doing my night and deep specialties.
The Geo 2 does pretty much everything I need it to for rec diving. In good light the screen is very easy to read and the numbers actually seem bigger and more legible to my 40 year old tiring eyes. That being said, I can see the big numbers but can’t read any of the subscripts. I always wanted the Perdix since I first picked one up and seemingly knew how to do everything I needed to with it, without ever seeing a manual. The Geo 2 is a different experience, where I have a bunch of dives on it and am still learning how it works just for rec diving. I felt weird about spending $1000 on a dive computer when I had 10-15 dives under my belt so I bought the Geo to get started with AOW and a couple of specialties.
There are a few things that made me splurge for the Perdix. At the moment it’s hard to say it was worth $1000 but I think I’ll feel better about the purchase with time. The Geo is tough to read in low-light situations - the backlight is just OK, requires a button press, and only stays on for 10 seconds max. I have a few night dives under my belt (starting the Night dive specialty this weekend) and I don’t like my computer being invisible without having to push a button. A few other things that have been bugging me are the alarms: 1) P02 has an alarm setting, but gives a WARNING that you can’t change/disable at 0.2 before your setting. 2) The Tissue Loading Bar Graph (TLBG) is pretty low resolution, and fills to it’s rec limit while I still have upwards of 20 minutes of NDL time remaining. So I’ve been feeling kind of blind to my actual tissue loading/limits, and don’t like being WARNED (blinking lights, beeping, flashing screen) about P02 when I’m well within my dive plan. Last, the Geo is decent looking but too big and bulky to be a daytime watch, and an actual watch strap pretty much sucks for donning over a wetsuit. Last, I wanted to check firmware to see if any of this has been updated. The manual says you don’t need to send the computer in, but you need a $100 cable. I don’t want to spend another $100 on the Geo. I’d like to be able to download my logs but for some reason the whole Geo package doesn’t seem worth the cost.
The Geo does a good job at what it does - there’s a reason it’s highly recommended for a relatively inexpensive dive computer. I feel safe and comfortable with it, and could tune in an algorithm that suits me the best for daily diving.
The other thing that made me get the Perdix is having everything in one place: for night dives, it’s nice to have gas pressure, dive info, and compass all in one place and always lit up. I”m scheduled to have Rescue Diver and 4 more specialties completed in the next month, so I that helps justify the expense I guess.
I did my first dives with the Perdix. Honestly the first thing I thought was, “Wow, the Geo is actually easier to read underwater!) and that was kind of disappointing. The Geo’s numbers are bigger, and the Perdix suffers from glare on the screen when diving during the day in crystal clear water. The second thing I noticed is my Perdix went into Deco while I still had 10 minutes of NDL left on the Geo. Fortunately that could be changed in the settings. I was surprised at how significant the difference is between ‘medium’ and ‘low’ conservatism on the Perdix (rec mode). The Perdix rec mode is more conservative than DSAT and that can’t be changed - only in tec mode, which has a different set of features (no auto safety stop timer, for example).
About algorithm: I’ve been diving the Geo mostly on DSAT, but recently switched to PZ+. Mostly because it’s super disappointing to do a deep wreck dive with nitrox, and have the rest of the boat diving Suunto and ascending when I still have 15 minutes of NDL left. But also, I’m in my first year of diving and felt that a little conservatism isn’t a bad thing anyway. Moving the Perdix to Rec, Low Conservatism is quite similar to Geo PZ+ at depth. But this is for the first dive only! Perdix was giving me more NDL on second and third dives, both on Nitrox and air. I did max depths of 108 - 99 -65 for my 3 dives on Sunday. As I said, Perdix Med got deco’d on the first dive with 10-12min remaining on Geo 2. Then I switched conservatism and it reversed.
Oh: The Geo 2 can’t change algorithm for 24 hours once it starts monitoring nitrogen. So you can’t try the 2 different algorithms back-to-back, even on 2 diving days since it’s less than 24 hours since you got out of the water. I dove in Fiji for 2 weeks, and once I got wet I was locked into the algorithm I had set.
Here’s first dive NDL limits: Geo PZ+ vs Perdix Bühlmann Low Conservatism (45/95)
Depth / Geo2 Air / Perdix Air /Geo2 32% /Perdix 32%
50.) 65. 76. 117. 157
60.) 48. 51. 74. 87
70.) 35. 36. 54. 62
80.) 26. 27. 42. 45
90.) 19. 21. 33. 34
100.) 16. 17. 25. 26
110.) 12. 13. 20. 21
120.) 10. NA. 17. NA. Perdix and I both know better.
130.) 8. NA. 14. NA.
Obviously the Perdix is something I can grow into. But honestly I thought about returning or selling it at first. Maybe one day I’ll consider tech (deco) diving and be thankful. Or maybe I’ll get used to having everything just where I need it on my wrist this weekend while doing my night and deep specialties.
