Question 1

Does this unit detect and mesure the radiation from a smoke detector?

Accepted Answer

The GM tube of the GMC-600 Plus is a pancake one with a thin Mica Window. This allows  also Alpha radiation to enter the GM tube and to detect it. A smoke detector can work with Am-241 isotopes and uses Alpha radiation for smoke detection. But all detetctors I know are very well shielded, so no Alpha radiation weill leave the smoke detector. Therefore, no external radiation detector will be able to detect the internal Alpha radiation of Am-241!
Regards
Uwe Z.

Question 2

Is it possible to end up buying a returned unit that was used and exposed to contaminated dust or materials? On amazon, you end up with returned items

Accepted Answer

Even though the seller responded to this question saying they will never themselves sell used products as new, that is probably the truth.  Amazon itself, on the other hand, does resell used products as "new" products.  When a product is returned to an Amazon warehouse, they will attempt to sell that product to the next customer as a brand new product even though it is a used product rather than trying to RMA the item.  Given that this product is likely to be used around a variety of hazardous radioactive sources, Amazon's current policy of reselling used products as new products is a huge problem.  This seller really should just sell direct online (via Square, Stripe, etc.) rather than through Amazon's tainted supply chain.  Or come up with a tamper-evident mechanism (e.g. tamper evident bank deposit bags) that customers can use to confirm that they did indeed receive a genuine, untouched, brand new product and also tell customers how to confirm for themselves that they indeed received a brand new product.

Question 3

will it detect radiation in water?

Accepted Answer

If your looking to "see" the radon particles in the water probably won't notice much difference between the water and background radiation unless it was a significant amount...

I would recommend putting the water in a glass or beaker and set the monitor on top to make readings...

I may try that myself and see what results are if any..

Question 4

How far should I let the battery run down before recharging?

Accepted Answer

20% would be the max if used on a regular basis.  Same rules as a cell phone, both li-po batteries.  Charge at 20% or more, try not to go below that 20 unless the situation is critical.  If used rarely, then charge when it gets at 50% and that's because if and when you really need it and it's dead, well it's dead and useless at that moment.  Hope this helps.

ASIN	B0FHGKCT8D
Best Sellers Rank	#91,469 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #12 in Lab Geiger Counters
Date First Available	July 14, 2025
Item Weight	1.6 pounds
Item model number	GQ 600 PRO
Manufacturer	GQ Electronics
Product Dimensions	5.1 x 3.1 x 1.6 inches

GQ 600 PRO Geiger Counter Nuclear Radiation Detector – Dosimeter for Alpha, Beta, Gamma, X-Ray – Portable Radiation Monitor with Real-Time Data, Global Data Sharing, LCD Display & USB

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