SPG vs tank checker gauge

[icechip]

This season, I notice my tank checker gauge is consistently reading the tank pressure at about 400psi more than my SPG. It will read tank at 3000psi but then I attach the SPG and it will read 2600psi, not sure why the discrepancy? Is it time for a new tank checker? Can I fiddle with the current one and maybe 'fix' it?

 

[lexvil]

It’s time to take a guess and change a gauge, my bet would be the SPG being off because those get banged around more, unless you dropped the checker, find another gauge to test with.

 

[icechip]

I think you're right. I dug out an old back-up SPG and it read much closer to the tank checker. So the SPG on my rig is the suspect one. Good to narrow it down! Thanks.

 

[Jack Hammer]

I think you're right. I dug out an old back-up SPG and it read much closer to the tank checker. So the SPG on my rig is the suspect one. Good to narrow it down! Thanks.

Yeah, I've had a few gauges get less accurate over time. I have a digital gauge on my fill whip that is super accurate. I'll use that occasionally to get a baseline reading on a tank and then check all my stage/deco/bg regs to see how far off they have gotten and if replacement is warranted. Digital gauges are pricey so see if your shop has one you can check your tank checker against.

 

[vjb.knife1]

Gauges need to be calibrated periodically to remain accurate. Your Local Dive shop should be able to adjust these gauges in most cases.

 

[AfterDark]

I have 4 SPGs none of them will give me the same reading on the same tank. I think it's the nature of the beast.

 

[rjack321]

Gauges need to be calibrated periodically to remain accurate. Your Local Dive shop should be able to adjust these gauges in most cases.

What SPG is adjustable?

 

[broncobowsher]

What SPG is adjustable?

My thoughts exactly. They are sealed and done. Don't work right, get a new one. DGX has them for a good price. Get a new spool while at it.

Which gauge is accurate? Find someone with a reference gauge and use that. We have an instrumentation lab at work that has gauges calibrated all the way back to the national standards. I've only used them for personal use a couple of times. I know they can do high pressures but only used them for setting tire pressure gauges.

So without access to standards, looking at your numbers. I see a 3000 and 2600 PSI. If the shop was short filling people to 2600 there would be a lot of outcry about it. So they probably really are filling to 3000. That is probably the correct reading.

 

[Lostdiver71]

And that is the reason I trust my pressure transmitter over any analog gauges. The pressure transducers are much more reliable and accurate.

 

[fisheater]

Reminds me of the saying that "A man with a watch always knows what time it is. A man with two watches is never sure."