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How to use PR-10,000

Learn how to correctly use PR-10,000 Phosphate Remover Concentrate in a swimming pool. PR-10,000 doses, how to add, and mistakes to avoid.




PR-10,000 is our concentrated phosphate remover, and it reacts quickly if phosphates are present in your water. It can be as simple as figuring out the correct dose and pouring PR-10,000 around the perimeter of your pool. Some pool professionals put PR-10,000 in a spray bottle and broadcast it across the pool surface instead. But PR can be used in several different ways.

Related: Phosphate Removal (Pillar 3)

Related: How to Implement the Orenda Program

You may need:

  • Plastic measuring cup (for liquids)
  • Commerical spray bottle (optional)
  • Phosphate test kit (optional)

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PR-10,000 dosing (per 10,000 gallons/38,000 Litres)

Use PR-10,000 as needed. If you know your source water contains phosphates, perhaps monthly (or even weekly) treatments make sense. Some customers prefer to add a strong dose at the beginning and end of the season only. The choice is yours.

One quart (32 fl.oz. / 0.94 L) of PR-10,000 removes approximately 10,000 ppb (µg/L) of phosphates in 10,000 gallons (38,000 L) of water. Most backyard swimming pools will never need such a heavy dose of PR-10,000 at once–with the exception of a green pool clean-up.

We recommend a limit for a single treatment at 8 ounces (8 fl.oz. / 0.25 L) per 10,000 gallons (38,000 L). This should remove up to 2500 ppb (µg/L) of phosphates, while not putting too much stress on the pool filter. When phosphates are removed, the water clouds and a precipitate begins to come out of solution. This fine white powder can build substantial pressure in the filter, and much of it will land on the floor of the pool. The heavier the dose and the higher levels of phosphates, the more cloudiness and dust.

Phosphate level (ppb, µg/L)

PR-10,000 dose per 10,000 gallons (38,000 L)
0-500 ppb 2 fl.oz. (60 mL)
500-1000 ppb 4 fl.oz. (120 mL)
1000 - 2000 ppb 8 fl.oz. (0.25 L)
2000+ ppb 10+ fl.oz. (0.3+ L)

Specific PR-10,000 doses for procedures

PR-10,000 is part of many Orenda procedures. Below is a table showing PR-10,000 doses for those procedures:

Procedure PR-10,000 dose per 10,000 gallons (38,000 L)
Normal max dose 8 fl.oz. (0.25 L)
Green pool cleanup 32 fl.oz. (0.94 L)
Sand filter purge 1/4 of the CV-600 dose*
"The Orenda Bomb" 16 fl.oz. (0.47 L)
Superchlorination 16 fl.oz. (0.47 L)

*Filter purge dose depends on the size of the filter, but always a 1:4 ratio with CV-600.

How to measure phosphate levels

There are several phosphate tests on the market, though most of them only measure orthophosphates. There are several other types of phosphates that could be in your water. We have no preference on which test kit you choose, just as long as the water sample is warm enough for accurate testing, and your test kit is used as directed, and not expired. 

A more reliable–but less specific–way to know if it's worth removing phosphates is with a small amount of PR-10,000 itself. We call this the red cap test. PR-10,000 comes in a bottle with a red cap. Simply drop a capful of PR into the water in one spot, and count to 30 seconds. If it clouds up larger than a basketball, the pool has enough phosphates in it that we feel it is worth treating. If not, your phosphate levels are nice and low...treatment is not necessary.

Then again, we have seen the red cap test create some big clouds! Here's a photo of a red cap test in a pool that should be treated:

Orenda PR-10,000 cloud, orenda pr10000, pr10000 cap test, phosphate remover cloud

Ways to add PR-10,000

To minimize the cloudiness–or at least spread it out for faster filtration–broadcasting or spreading PR-10,000 around the pool is a wise approach. Instead of pouring the entire dose in one single spot, spreading it around allows for more water to be treated faster. More dispersed phosphate precipitation means faster filtration and faster clearing of the pool.  What does not get filtered out will fall to the floor and need to be vacuumed. Do NOT add PR-10,000 directly into a skimmer or gutter.

Pouring. The recommended way to add PR-10,000 is to pour it around the pool perimeter. This should be done while the pool is circulating, though it does not have to be. If you are regularly using PR-10,000 to maintain low levels of phosphates, small doses each week, or each month may be preferable to heavy doses once or twice a year (it will certainly be less of a mess). 

Spraying. Another way is to broadcast PR-10,000 using a spray bottle. We recommend knowing how much each spray is, which you can test with water and a measuring cup at home. If you know each spray is 0.25 fl.oz., for example, then four sprays is one ounce. Figure how many sprays you want to use, and you're good to go.

Automating. Commercial pools–and some high-end residential pools with chemical automation–may have the ability to put PR-10,000 on an automated feed pump. While this is great for CV-600/CV-700 enzymes, we prefer manual additions of PR-10,000 on an as-needed basis. Unlike enzymes or SC-1000, there is no residual left behind with PR-10,000. It reacts with phosphates and falls out of solution for vacuuming or filtering out. While some pools do put PR-10,000 on feeders, we think this will cause you to overuse the product.

Again, DO NOT pour PR-10,000 directly into a skimmer or gutter.

Filtration and vacuuming

When PR-10,000 dust falls out of solution (wow, that cloud 😶‍🌫️🎶), it will leave a mess behind. Much of it will land on the floor of the pool, but a lot will be pulled into the filter. Filter pressure will build.

Warning: Do NOT use PR-10,000 with a D.E. Filter unless you are planning to clean the filter the next day, and are prepared to dump and replace the D.E. filter media. 

If you shut off circulation about 10 minutes after adding PR-10,000, the cleanup is as easy as vacuuming to waste. If not, or you're doing small incremental doses, the cleanup will involve cleaning or backwashing the filter too. In both cases, vacuuming is recommended. Dust will fall.

What if PR-10,000 does not cloud the pool?

That's GREAT! No cloud means your phosphate levels are very low. Savor the moment.

Mistakes to avoid

  • PR-10,000 itself is an acidic chemical. Keep that in consideration for how you store it.
    • Do not use a brass spigot if pouring PR-10,000 from drums into smaller bottles.
  • Do not mix PR-10,000 with any other chemical, including Orenda products. Just because they are compatible in pool water does not mean they are compatible in the same bottle.
  • Do not overdose PR-10,000. When in doubt, err light.
  • Do not let PR-10,000 (or any other Orenda product, for that matter) freeze. Store in a climate-controlled area.
  • Do not heavily dose a pool that has a D.E. filter without being sure you can come back the next day to clean the filter and replace the media. PR dust will build pressure rapidly, which can crush D.E. grids.

Other uses for PR-10,000

PR-10,000 has some other properties beyond just phosphate removal. PR can be a powerful cleaner against calcification and 'gunk', particularly residue from cal hypo feeders. Here's a video showing PR-10,000 on a rag, easily cutting through caked-on calcium residue in a filter of a cal hypo pool:


Another thing PR is great at is cleaning dirty sand filters–when used in a 1:4 ratio with CV-600 or CV-700 enzymes. Here's the sand filter purge procedure: