What PoolBoss Says
Borates are worth it on pools that fight rising pH every week. Held at 30-50 ppm, they buffer pH, cut how much acid a pool needs and mildly suppress algae. On a service route they pay off on plaster and salt pools with heavy pH drift, and they are rarely worth the first dose on pools whose pH already holds.
Every route has a handful of pools that eat acid. You bring pH down to 7.5 on Tuesday, and by next Tuesday it is back at 8.0 with a scale line starting at the tile. The tech carries an extra jug for that subdivision, and the customer notices the cloudy water before you do. Someone on a forum says borates fixed their pool, and a retailer has a bucket of borate product at a price that makes you hesitate before trying it on 40 accounts.
The question for an operator is not whether borates are nice to have. It is whether the money spent on the first dose comes back in acid, visits and callbacks on a specific pool. Below is what borate actually does in a swimming pool, what it costs to bring a pool to 40 ppm with borax or boric acid, how a 44-pool route measured the result, how to add it without sending pH to 8.5, how to test and hold the level, and the accounts where it is money wasted.
At a glance
Key takeaways
- Borate only the pools with heavy upward pH drift, not the whole route.
- Hold borates at 30-50 ppm, and never go above 50 ppm.
- Budget roughly $60-95 in borax or boric acid to bring a 15,000-gallon pool to 40 ppm, one time.
- If you use borax, plan on about 1 gallon of muriatic acid for every 15 lb, added in stages.
- Fix total alkalinity before borating, and consider running it lower, around 60-80 ppm, afterward.
- Log acid dosed per visit for eight weeks before and after, so the decision rests on numbers.
- Ask about dogs that drink from the pool before adding borates.
Are borates worth it in a pool?
Yes on the pools with persistent upward pH drift, and usually no on the rest. Swimming pool borates at 30-50 ppm slow the pH climb that comes from aeration, salt cells and fresh plaster, so a pool that needed acid at every visit needs it every second or third visit instead. That saving is real on a pool taking a quart of muriatic acid a week. On a vinyl pool that moves 0.1 a month, there is nothing for borates to save.
The rule most routes land on is to treat borates as a fix for a pool, not a policy for the route. Pick the accounts where acid demand is highest and the customer is staying, borate those, and measure. The table below sorts typical account types by how their pH behaves. The drift and acid figures are rough ranges for a 12,000-15,000 gallon residential pool with alkalinity in range, not guarantees.
| Account type | pH drift pattern | Acid used per month | Borate verdict |
|---|---|---|---|
| Plaster pool with a waterfall, spillover spa or hard fill water | Rises 0.3-0.5 a week | 3-5 quarts | Strong candidate |
| Salt pool | Rises steadily while the cell runs | 2-4 quarts | Strong candidate |
| Plaster pool, still water, normal fill | Rises 0.1-0.2 a week | 1-2 quarts | Only if callbacks are frequent |
| Vinyl or fiberglass, no water features | Nearly flat | Under 1 quart | Skip |
| Pool with a dog that drinks from it | Any | Any | Skip |
What is borate, and what does it do in a pool?
Borate is the pool trade's name for dissolved boric acid and its salts, added from borax (sodium tetraborate) or boric acid to buffer pH. In water around pH 7.5, most of it sits as boric acid, and as pH starts to climb it releases hydrogen ions that push back against the rise. That is why a pool at 30-50 ppm borate holds pH noticeably steadier than the same pool at zero.
Borates work alongside total alkalinity rather than replacing it. Alkalinity mostly stops pH from falling, and it is also the reason pH climbs, because carbonate in the water gasses off as carbon dioxide when water is splashed or sprayed. Borates resist the upward move specifically, so a pool with borates can often run alkalinity lower, around 60-80 ppm, and lose less carbon dioxide in the first place. Both effects reduce acid demand.
There are two side benefits worth knowing and not overselling. Borates are a mild algaestat: they make it a little harder for algae to take hold, which helps a pool that blooms every August, but they do not kill algae and they do not replace chlorine or a real algaecide. Many customers also say the water feels softer, which is a real selling point on a pool they swim in daily. Borates do nothing for chlorine demand, stains or high calcium.
What it costs to bring a pool to 40 ppm
Bringing a 15,000-gallon pool from zero to 40 ppm costs roughly $60-95 in borax or boric acid at typical bulk prices, and often $150 or more with a branded pool borate product. That first fill is the whole objection, because after it borate only leaves the pool when water does. There is no weekly borate cost the way there is with chlorine or acid.
The dose math, with borate measured as boron the way most borate test strips and pool calculators report it, works out to about 7.4 lb of borax or 4.8 lb of boric acid per 10,000 gallons for every 10 ppm. Borax is cheaper per pound and easy to buy, but it has a pH around 9 and drives the pool up hard, so it needs muriatic acid to bring pH back, roughly 1 gallon for every 15 lb of borax. Boric acid barely moves pH and needs no acid, but it costs more per pound. A branded product is usually one of the two with a label price on top, and label directions govern over any rule of thumb here.
| Product | Amount | Acid to rebalance pH | Rough product cost |
|---|---|---|---|
| Borax (sodium tetraborate) | About 44 lb | About 2.8 gallons of muriatic acid | $70-95 including acid |
| Boric acid | About 29 lb | Little or none | $60-85 |
| Branded pool borate product | Per label | Per label | Often $150 or more |
What borates did on six pools in Mesa
The fastest way to know whether borates pay on your route is to borate a few problem pools and log acid use before and after. Take an operator running 44 pools around Mesa and Apache Junction. Eleven of their accounts were older plaster pools on hard fill water, most with a waterfall or a spillover spa, and every one of them took acid at every weekly visit. The two techs were carrying extra acid just for that subdivision.
The operator picked six of the eleven, all roughly 12,000 gallons and all with customers who had been on the route for years. Each got about 35 lb of borax, added over two visits with acid to bring pH back, for about $55 a pool in borax and acid plus a $25 bottle of borate strips shared across the six. Then the techs logged acid dosed at every visit for eight weeks and compared it with the five pools left alone.
The six borated pools went from about a quart of muriatic acid at nearly every visit to a quart about every third visit, while the five untreated pools kept taking acid weekly. At a quart a week, that is roughly 35 quarts a year saved per pool, around $50 in acid at $6 a gallon. On product alone the payback is about a year. The bigger return was the time and truck space. One of the six, a pool that went green every late summer, got through August without a bloom, though its chlorine was also held steadier, so the borates earn partial credit at most.
The measurement is the part most routes skip. Without a record of acid dosed per visit, the before and after is a feeling. With it, you can see the per-pool chemical cost the decision rests on, and decide on data whether the other five pools should be borated next season.
Adding borates without sending pH to 8.5
Add borax in portions over one or two visits, then bring pH back with acid in stages, and never dump the full dose and the full acid at once. A 44 lb borax dose added in one go can push a pool past pH 8.5, and chasing that with 3 gallons of acid in a single pour risks etching plaster and overshooting low. The steps below keep the pool in a normal range the whole time.
- Test first. Record pH, total alkalinity and calcium hardness. If alkalinity is far out of range, fix that before adding any borate, because borates layered on bad buffering make the pool harder to read.
- Split the dose. Add about half the borax on the first visit, broadcast across the deep end with the pump running, and brush the floor so granules do not sit on plaster.
- Rebalance the same visit. Once the borax has circulated for 30-60 minutes, retest pH and add muriatic acid in front of a return in portions, aiming for 7.4-7.6.
- Finish next visit. Add the second half, rebalance pH again, and let the pool circulate for a day before testing borates.
- Using boric acid instead? Skip the acid step, but pre-dissolve it in a bucket of warm water, because boric acid dissolves slowly and sits on the floor otherwise.
Testing borates and holding the level
Test borates with borate test strips or a titration kit a day after dosing, then about every one to three months. Borate strips read in bands, usually up to around 80 ppm, which is enough to confirm a pool landed in 30-50 ppm. A titration kit is more precise if you are borating many pools. Borates do not get used up, break down in sunlight or leave with chlorine, so the level only drops when water leaves the pool.
That makes the retest schedule event-driven. Heavy backwashing, a rainy week that overflows the pool, a leak or a partial drain each take borate with the water. A pool that lost a foot of water to an August monsoon and was refilled may have dropped from 45 ppm to 35 ppm. Top up with the same dose math on the gap between the reading and your target.
Record the borate reading on the visit, not in a note that nobody reads. It belongs alongside which readings are worth recording at every stop, because the trend is what tells you when to top up. In PoolBoss an operator can add borates as their own reading type with an ideal range, so a tech logs it from the app with the rest of the readings and a value outside the range flags on the visit and in the pool's reading history. That is tracking what each pool actually costs in chemicals next to what went into it.
When to skip borates
Skip borates wherever the pool does not have a pH drift problem to solve, or where the risk outweighs the saving. The most common mistake is borating a pool whose real issue is alkalinity. A pool at 50 ppm alkalinity still needs baking soda before anything else, and a pool at 150 ppm needs total alkalinity brought down first, not a second buffer on top.
- Vinyl and fiberglass pools with flat pH. A pool using under a quart of acid a month has almost nothing to save, so the $60-95 first dose takes years to come back.
- Pools whose pH keeps falling. Borates mainly resist pH rising, so a pool on trichlor tabs sliding toward 7.0 needs the approach for raising pH on pools that drift low, not borates.
- Dogs that drink the pool water. Borates are toxic to dogs that drink pool water regularly, so ask the customer about pets before you add them, and skip any pool where a dog drinks from it.
- Accounts you may lose. The first dose is an investment in the pool, and it leaves with the account. A customer who is shopping around or selling the house is not the one to borate.
- Commercial pools under a health code. Check your state's code and the product label before adding borates to an HOA or apartment pool, and never go above 50 ppm.
FAQ
Frequently asked questions
Can I use regular borax instead of a pool borate product?
Yes, plain borax from the laundry aisle is sodium tetraborate, the same active ingredient many pool borate products use, and it usually costs a fraction of the price. The two things to check are the box and the acid. Buy plain borax with nothing added, not a laundry booster with fragrance, brighteners or detergent in it, because those additives end up in the pool. Then plan for the pH swing: borax raises pH hard, so it has to be paired with muriatic acid, roughly 1 gallon for every 15 lb, added in stages rather than all at once. If you do not want to manage that acid step, boric acid is the alternative that barely moves pH, at a higher cost per pound. A branded pool product is fine too, it simply costs more, and its label directions are the ones to follow for that product.
Do borates replace algaecide?
No. Borates are a mild algaestat, which means they make it somewhat harder for algae to take hold, but they do not kill algae that is already growing and they are not registered as an algaecide. A pool at 30-50 ppm borate may go through a hot stretch without a bloom that it would otherwise have had, especially if free chlorine is also held in range. That is a helpful margin, not protection. If a pool turns green or shows mustard or black algae, treat it exactly as you would without borates: brush, shock to the right level for the pool's stabilizer, filter and clean. Keep using an algaecide where it already has a place in your routine, such as a pool that goes unattended for two weeks. The borate benefit that pays on a route is the pH buffering. Treat the algae effect as a bonus you do not count on.
Do borates work in a salt water pool?
Yes, and salt pools are often the best candidates for them. A salt chlorine generator makes chlorine in a way that pushes pH up steadily while the cell runs, and the hydrogen bubbles it releases add aeration on top, so salt pools commonly need acid more often than chlorine pools with the same alkalinity. Borates at 30-50 ppm slow that climb. They do not interfere with the salt reading or chlorine production, so the cell carries on as normal. Check the cell manufacturer's manual before adding them, since a few set their own chemistry guidance, and follow it where it differs. Add borates the same way you would on any pool, rebalancing pH if you use borax, and let the pool circulate before you judge the cell's output. Then log acid use for a few weeks so you can see whether the salt pool's acid demand fell.
Should I tell the customer before I add borates?
Yes, tell them before the first dose, both because it is a one-time charge and because of pets. Most customers never think about what goes into their pool beyond chlorine, so a short note explaining that borates hold pH steadier and may make the water feel softer usually lands well. It is also the moment to ask whether a dog drinks from the pool, since borates are toxic to dogs that drink pool water regularly, and a yes means skip it. Agree on how you will bill the first dose, either as a line item on the next invoice or folded into a price you already quoted, so it does not show up as a surprise. Put the conversation and the answer in the customer record. If the account later transfers to another tech, they need to know the pool carries borates, so they test for them instead of guessing why pH suddenly behaves.
How do I lower borates if I add too much?
The only way to lower borates is to replace water, because nothing added to the pool removes them. Borate does not break down, burn off or leave with chlorine, so a pool that landed at 70 ppm will stay near 70 ppm until water leaves. Work out how much to drain from the percentage you need to lose: to go from 70 ppm to 45 ppm, you need to replace roughly 35% of the water. Drain in stages if the pool's surface, water table or local watering rules make a big drain risky, and refill with fresh water. Rain overflow and backwashing take some borate out over time, but on most pools that is only a few ppm a season, too slow to fix an overshoot. The better answer is to avoid overshooting in the first place: dose for 40 ppm rather than 50, add the dose in two portions, and test before topping up.
Should I lower total alkalinity after adding borates?
Often yes, and it is where a lot of the acid saving comes from. Borates handle part of the job of resisting pH rise, so a pool that needed 100 ppm alkalinity to stay steady can usually run around 60-80 ppm once borates are at 30-50 ppm. Lower alkalinity means less carbon dioxide gassing off, which means pH climbs more slowly on its own. Bring alkalinity down gradually over a few visits with acid, aiming for the low end only if pH is holding well, and watch calcium hardness on plaster pools, since lower alkalinity makes the water slightly more aggressive. Keep an eye on the pool's saturation index if you track it. If pH starts dropping between visits after you lower alkalinity, you went too far, and a little baking soda brings it back up. Change one thing at a time so you can tell which change did what.
