Boric Acid

[WuhWuzzat]

Awaiting delivery on a new tub and I am looking to add borates to my water after balancing. I prefer to use boric acid rather that the borax/MA method. Where have you folks had luck finding the stuff?

I see the local big box stores carry roach killing powder which according to the MSDS is 99% orthoboric acid. Would this suffice?

[endorfin]

It is the same, just make sure there is no dye in the product. There was a thread earlier this year where the spa owner ended up with a blue dye ring after adding roach killer.

[waterbear]

You can order boric acid from The Chemistry Store.

[JimKW]

I bet my wife would love getting in a hot tub after I added roach killer!

[Fatlip]

I get boric acid at Rite Aid, comes in 8oz bottles. I like boric acid the best because it dosent move the ta or ph at all.

[ataDude]

Awaiting delivery on a new tub and I am looking to add borates to my water after balancing. I prefer to use boric acid rather that the borax/MA method. Where have you folks had luck finding the stuff?

I see the local big box stores carry roach killing powder which according to the MSDS is 99% orthoboric acid. Would this suffice?

I bought a 15 pound tub from where waterbear stated. Was about $40 including shipping. Still a lot cheaper than $8-10 per eight ounces at the drug store.

.

[waterbear]

Borax and acid is cheaper still and NOT a lot more work. For a 300 gallon tub you would need about 2 cups of borax and 1 cup of muriatic acid. One box of borax is $3.00 and has over 26 doses for a 300 gal tub @ about $.11 per application.

One gallon of muriatic acid is about $5 and has 16 doses @ less than $.32 per application for a total of about $.43 per application.

The same 15 lb container of boric acid from the Chemistry store is over $43 to my location in N. Fl so it becomes even more expensive for me.

For boric acid you would need 1.5 cups for the same size tub at a cost of $.54 per application (given the price of $40 for 15 lbs with shipping.) While 11 cents might not seem like a lot of money it is over a 20% increase in operating cost for borate addition.

The applicaton of borax and acid is easy. Get a small bucket and half fill it with spa water, add your acid to it, turn on the spa circulation, dump in the borax, pour in the bucket of acid and water, circulate for about an hour until everything is dissolved. Adjust pH in 24 to 48 hours.

The application of boric acid does not save that much time in reality. Turn on the spa circulation, dump in the boric acid, circulate for about an hour until everything is dissolved. Adjust pH in 24 to 48 hours.

In either case you will probably have to "fine tune" the pH and in both cases you have to get the TA into the desired range before you add the borax so, in most cases, you will be working with either dry acid or muriartic acid anyway. Adjusting the TA is the most time consuming part of the process.

Don't forget to get either LaMotte or Proteam borate test strips! Should be less than $15/tube these days for the LaMotte ones. The AquaChek strips are much harder to read so I do not recommend them. You will probably have to order them online since they seem to be rarely stocked in the brick and morter supply stores.

[WuhWuzzat]

I appreciate the responses.

Being that boric acid is relatively pH neutral, I figured that method might be easier as I imagine it would be easy to overshoot one's target level with the introduction of muriatic acid in such a small quanity of water. However, if I am most likely going to need to "fine tune" my pH using either method, I might just take WB's advice. I already have MA on hand as I have an inground swimming pool with a SWG that requires periodic pH reducutions, so I'll just need to purchase some borax. For those that are interested, I'll post back to let you know how it went.

[waterbear]

FWIW, borax is EXCELLENT in a pool with a SWCG! Drop your TA to 70 ppm, bring your CYA to the manufacturer's recommended level (usually 80 or 100 ppm) and add the borax and acid in two batches. Broadcast half the borax and then add half the acid (either diluted in a few buckets of water or poured slowly into a return stream) then add the rest of the borax and acid, Filter continuously for 24-48 hours and readjust pH to 7.6. Don't lower the pH below 7.6 and wait for it to rise above 7.8 before dropping it back to 7.6. You will find that you will have much better pH stability.

Oh yeah, you will need 60 oz by weight of borax and 30 oz by volume of 20 baum muriatic per 1000 gallons to raise the borate 50 ppm. (Remember each box of borax is 4.75 lbs or 76 oz). You can round the acid off to a quart per 60 oz of borax will no ill effects. As long as the pH stays above 7.0 after the addition you are fine since it WILL rise.