Time to buy a scale

I went with this one. They're probably all the same, just read a lot of good things about that one.

 

Very simple to use. There are dozens of them on EBay from that seller, so you shouldn't have an issue getting one fairly easy. If/when you get it, ensure you check to see it works properly as soon as you get it. The seller will replace a defective scale.
The easiest part is you can put your ferts onto the plastic case and never have to get them onto the scale itself. It was designed as a gunpowder scale, so the small granules to be weighed were thought out well.

 

Just a tip, though one calibration weight I am pretty sure works across the board when digital: there's lots of little things around you can use to check the weights we normally use. For example, any US bill (like a dollar) is 1 gram.

I have an expensive OHAUS N12120 I got from the pile of broken scales at school (back when I went to school). Just needed a couple leads inside resoldered! But my point is that a buddy of mine got a 10mg palm scale (like yours) from a smoking accessories store, and we spent about a couple beers worth of time measuring junk around my apartment. They are pretty much the same -- if you breathe on mine it changes the weight (seriously) but they settle to the same. In fact I have thought about downgrading just to get the space back on the counter I keep my nerd stuff.

HTH

 

Good stuff. Very accurate tool as far as I can tell.

 

I'm just a bit surprise as any high quality branded scale with a 0.01g precision will cost you above 150 USD. Make me doubt of teh real value of a 0.01g scale costing 20USD.
0.01g is really small. A good test would be to put on the scale the same granules quantity and check for reproductive results. I doubt it will work with this scale. Also, I will be concerned on the long term deviation.

What makes be more suspicious is the calibrating weigh: 100g when the scale is also specified to be 100g maximum capacity. A real scale at that precision can't be calibrated with one point set at its maximum range as it just won't give you any good precision range.

If you dose dry, better spend some 60 USD in a 0.1g high quality precision scale or use the Salifert test kit blue spoons (in KH and PO4 tests): a flat spoon will contain 0.2g powder

If you prepare stock solutions, a +/- 1-5g precision is more then a "Deluxe" result. The bigger the volume of stock solution, the more error margin you have. A quality kitchen scale at 30USD will give you a real +/-2g precision

For an example, let's consider a 10gal tank:
15g KNO3 in 250ml DI ---> each ml of this solution will add 0.97ppm NO3 to the tank
16g will add 1.03ppm
17g ---> 1.1ppm
20g ---> 1.29ppm

So, a +/-5g precision ends you with a +/-0.3ppm error margin. Who really cares about it???

Go with a kitchen scale for stock solutions, it'll be a really better investment. For direct dry dosing, either invest in a good 0.1g precision scale (60-90 USD) or calibrate some dosing spoons in a drug store or jewelery, they will do it free for you

 

You can buy the same scale from that companies store here for $79. Does that make it a better scale?

 

I just use the dash/pinch/whatever on the assumption that they're 1/8,1/16,1/32 or close enough. Dosing is a scoop of them as needed and I don't bother to pack/flatten other than shake them out a bit. Often I'm after the "heaping" measurement anyway. I could see the use of the higher precision but for my purposes I just don't need it. My repeatability on my dosing would give anyone interested in chemistry fits I'm sure.

-
S

 

I didn't know a dollar weighs 1 gram. Very cool. I also got one of the scales from AWS. For what ever reason I thought it would need a 50 gram weight for calibrating it, only to find it uses a 100 gram weight. So I tried weighing a few things. Belly button lint, 0.00g, one dollar 0.99g, the 50 gram weight is 50.1 grams. The realization that EI means never having to worry if I'm 10% off my dose, priceless.

 

Real quality scales at 0.01g precision usually have a certification label + factory calibration service

Again, in my expierience and based on what I know, those cheap 0.01 and 0.1g scales are very fair and will go out of calibration quickely. Furthermore, you'll discover that a 100g limit is a contraint when you want to make stock solutions and use containers. The total weigh, if above 100g can harm the scale. A kitchen scale at 1g grading with a +/-2g precision and a 500g tolerance will be a much better investement in the long run. Like with CO2 and many things in life, you get what you pay for. So don't expect a good quality 0.01g precision from a 20$ gadget. The point is that even if it is precise in some ranges, it can deviate by many grams in other ranges from 0-100g. That's the main issue with these scales. High quality scales will have their precision maintained on the whole weigh range. Low quality ones can be out by many grams in some ranges

Now, some people feel more confortable when their scale shows them a 0.01 display, giving them a false impression of security, it's their choice, but at least it can be now an informed choice

 

I have two sets of scales. One is a nice one from AquaticEco.com that measures to 0.1 gram and has a max capacity of 200 grams. The other scale measures to 0.001 gram. It has a 50 gram capacity.

 

I also have a 0.1g precision scale by the way, 220g maximum tolerance too. I quiet no longer use it to prepare stock solutions. Only to dry dose K2SO4

 

I'm not sure what the problem is.

In one statement being off by as much as 5 grams is not an emergency but using low cost scales because of there limited range should be avoided. I have yet to need a scale to weigh anything over 50 grams making 500mL stock solutions. Were as with yeast preparations, I need to weigh out measures under a gram. I'm not sure if I need a scale that can measure a quarter pound. Maybe back in the day, but not now. As for calibrating the scale, I check it every time I use it. I might get two 25g weights some day (hmmm, what would half a beer weigh?) and check the scales accuracy at 25, 75 and 100g weight. Until then, I can check 1g and 50g. This is close to anything I've been weighing. If the scale breaks, I'll be happy to let you know. I looked at some of those kitchen scales - they take up a lot of space. Why be so contrary? Cheep is as cheep does. We got it.