Looking for a good low pressure gauge for a presta and schrader valves

Define "low."

Something that measures up to 30-50 lbs

Just saying, automotive tire gauges excel in that range of pressure. Schraeder only I am afraid. But I would be shocked if 'fatty' tubes came in Presta. Of course I know nothing about it. Nothing at all. Anyway, that was hardly helpful. I try to be helpful when possible. Here is what I know. I haven't owned (or needed) a tire gauge since I started using Joe Blow (Topeak) floor pumps which have perfectly serviceable gauges built in. I trust mine to measure pressures as low as 20psi and up to 100+ psi, and if the pump is off a pound or two at 30psi I DOUBT anything bad is going to happen. TL;DR: ANY tire gauge sold that reads Presta and Schraeder can be used for the o.p.'s purposes. Some are even digital, but the sensors are analog so the accuracy of the digital unit isn't any higher. It just seems that way. This is intentional.

Never used it so can't voucher for it, but it seems to cover your range and handles both valve types.
https://www.amazon.com/EyezOff-EZ05-.../dp/B01HBMENXO

From what I am learning (I am new with the fat bike) you wan a gauge that can measure 8-12lbs low for beach higher for trails
So I was asking about a good one to be accurate with pressure

https://www.amazon.com/Schwalbe-6010...omotive&sr=1-1

This one does the trick for me

That's not low.

Search for the "accugauge" on Amazon. There's a model that goes up to 15psi for fatbikes. Higher than you'll ever need to go.

Thanks does that gauge do both type valves

https://www.amazon.com/Accu-Gage-Pre...gateway&sr=8-2

I got a Planet Bike tire gauge that measures up to 15psi.

^^^Have same gauge, perfect for fatties!

Schwable airman digital Guage, accurate down below five psi. Replaceable battery as well. Shimano also made one but the battery was not replaceable but it was a little cheaper.

pro tip, from a long distance rider, for one of your presta valves use a schrader adapter as a the valve cover. It will save you should you find yourself needing air at a station.

Are there fatbike with Schrader valves?

0-15 psi AccuGauge is my choice.

30-50lbs (psi) is low?

If you want low (up to 20psi, but especially for under 5psi), for a fat bike, MEC has a really good one
https://www.mec.ca/en/product/5053-079/Fat-Max-15-Gauge

I've got the same one, didn't know the name till I looked at mine this weekend
Easy to use and what I thought was 15 pounds on the pump gauge was only 10

Go by feel. It is a fat bike. No sense in arguing or worrying about it. Adjust a accordingly to the terrain. Don’t micro manage a fat bike

Get the jumper cables out. But seriously, with the exception of big box store bikes, most fatty tubes are Presta.

FWIW, on my bike, I use the gauge as a reference and a starting point (5-6 psi) and drop the pressure from there as needed for conditions. With winter riding, pressure can vary greatly with temperature changes - never adjust your pressure until the tires have acclimated to the outdoor temperature. With that, there is no real need for a gauge as you will just be squeezing the tire to guesstimate if you have let enough air out.

Fatties have presta valves (although I'm sure some have shrader as well).

And 20psi+ is way too much for most fat bikes. For riding in the snow, a pound or two of pressure can make a big difference