Need instructions on raising borates.

BEFORE ADDING BORATES BRING YOUR TA TO DESIRED LEVEL. FOR A SALT POOL THIS WOULD BE 70 PPM!

1) get a tube of LaMotte borate test strips
2) test your borate level (hint: read the strip in sunlight, not artificial light.
3 figure out how much borax and acid you need to bring the level up to 50 ppm for your pool (to rasie 1000 gallons 10 ppm you need 12 oz BY WEIGHT OF 20 Mule Team borax (sodium tetraborate decahydrate) and to keep the pH neutral you will need 6 oz of muritic acid.
4) WITH PUMP RUNNING add half the acid and half the borax. brush the pool well to mix everything, add the rest of the acid and borax, brush again, and let pump run 24/7 for 2 days. Check borates and pH and make any minor adjustments needed. If the pH is low just aerate or do nothing and it will rise. If high add more acid. Borates should be right on the money if you calculated properly. If they are a bit high don't worry about it. If they are a bit low add more borax and acid to bring them up.
5) When borates drop below 30 ppm bring them back up to 50 ppm.

Here is an example:
You have a 12000 pool and your current borate reading is 15 ppm. You need to raise the borates by 35 ppm to reach 50 ppm.
Since 12 oz of borax raises 1000 gallons then 12 x 12 oz (144 oz) borax raises 12 x 1000 gallons (12000 gallons) by 10 ppm SO
144 oz borax raises our pool 10 ppm and will need 72 fluid ounces of muriatic acid to keep the pH in line.
Since we need to raise the borates by 35 ppm we need to multiply these numbers by 3.5 (3.5 x 10 ppm = 35 ppm)
SO we would need 3.5 x 144 oz borax in total (504 oz). Since borax comes in 76 oz boxes (4 3/4 lbs) we would need 6 boxes and another 3 lbs out of a 7th box. You can estimate this as 6 2/3 boxes or (what I would do) is add the 6 boxes and weigh out the 3lbs out of the 7th box.
You would need a total of 3.5 x 72 fluid oz of muriatic acid ( 252 oz or just a hair under 2 gallons (I would round it off to two gallons. If the final pH is too low you can either add a bit more borax or arate the water to bring the pH up).

SO to bring ujp the borates in our theoretical 12 k gal pool we would add:
1 gal of acid and then 3 boxes of borax and brush.
then add the next gallon of acid and the rest of the borax (3 more boxes and 3 lbs), brush again, and let it circulate for 2 days. Test borates and pH and adjust as needed.

FWIW, 5 boxes of borax in a 17k gallon pool will bring up the borate level by about 19 ppm and if you backwash your filter the level would be lower so your first step is to test the borate levels and the LaMotte strips are the easiest way to do so. Do not get the AquaChek borate strips, they are very difficult to read.