Using PhosFree for algae control

I have a 10,000 gallon above ground vinyl pool with a saltwater system that I have treated for high phosphates for two or three years now even though I have never had algae problems. Phosphate levels are tested at Leslie's Pools. I have read some forums regarding the use of PhosFree and now I wonder if I should be using it. I am getting ready to open my pool for the season and I always buy the opening kit from Leslie's that includes the PhosFree product.
After treating with PhosFree the levels go down, but then will gradually go back up. Do I need to be using it or something else?

This is going to be my sixth or seventh year with the pool and the phosphate problems didn't start until two or three years ago.

What makes you think you had a problem? Did you get an algae bloom? Does your chlorine level keep dropping to zero?

Or is it just that Leslie's TOLD you that you have high phosphate levels? (so they could hook you on phosphate removers)

1. Maintaining very low phosphate levels (< 0.125 ppm) DOES inhibit algae. But, it doesn't kill algae.

2. Many, maybe most, pools have NO trouble with algae if effective chlorine levels are maintained -- chlorine levels that are 10% of the CYA level or higher will do it.

3. A few pools have problems with recurrent mustard algae, in spite of adequate chlorine levels. I don't know why this happens.

4. It's more difficult to maintain low phosphates than most realize. Many of the tests are very inaccurate; city water may have 2 - 3 ppm (2,000 - 3,000 ppb) of phosphates; many commonly sold pool chemicals CONTAIN phosphates, or turn into phosphates.

5. It's completely useless to use 'some' phosphate remover: until phosphate levels go below 500 ppb (0.5 ppm) there's no effect. To be fully effective, you need to go below 125 ppb (0.125 ppm).

6. Phosphate removers vary greatly in quality. By far the best choice is Orenda's PR10000 removing 10,000 ppb (10 ppm) from 10,000 gallons of water. I've recommended other products in the past, only to discover they were playing games with the concentration!

Orenda PR10000 Phosphate Remover @ Amazon

7. After testing numerous phosphate kits and strips, only the AquaChek and Taylor tests seem to be accurate enough to be useful, and the AquaChek is only helpful once you've greatly reduced the phosphate levels. Both kits are a bit of a pain to use.

Hach (AquaChek) Company 562227 Phosphate Test Kit @ Amazon
Taylor K1106 Phosphate test @ Amazon

8. Using phosphate removers *may* be worth trying *if* (a) you have recurrent algae in spite of reasonable chlorine levels OR (b) you are frequently away from the pool for more than 3 days, but ONLY if you are able to (a) test accurately, (b) dose adequately, & (c) avoid using of phosphate sources.

9. Some phosphate removers may cloud the water temporarily; all can cause the filter to clog somewhat. As a result, if you have typical levels of phosphates in your pool, it may take a week or more to lower phosphates sufficiently to be effective.

If you have a phosphate level AT 125ppm, as I do, based on the Taylor kit reading, would it be worth a dose of Phos-Free to try and lower it even more? If, as you say, there are seemingly many more sources of phosphates, why not try to get it closer to zero (or at least below 100 since I doubt zero is realistic) to give you a buffer zone should your city water add it during normal fill-ups from evaporation or from regular chemical morphing into even more phosphate stuffs.

I think you'd be better off saving it.

Go ahead and test your FILL water. Then we can figure out how to dose your pool to compensate for water additions, ie, 1" of added water = X oz of phosphate remover.

Also, Phos-Free is one of the more expensive ways to remove phosphates. Currently the Kem-Tek product (link below) seems to be the lowest cost ($'s/ppm PO4 removed) product. So, if you have Phos-Free already, don't throw it away. But, don't buy more, either since it costs a significantly more than the Kem-Tek product does.

Regarding other sources, as long as you use unblended chemicals (which we recommend) and avoid pool 'steroids and vitamins' -- products from United Chemical, Jacks Magic, SeaKlear, Natural Chemistry, etc -- and aren't having to deal with metals in your pool, you shouldn't be adding any phosphates, except via your fill water.

[ Links to products previously listed here removed!]
Phosphate removers vary greatly in quality. By far the best choice is Orenda's PR10000 removing 10,000 ppb (10 ppm) from 10,000 gallons of water. I've recommended other products in the past, only to discover they were playing games with the concentration!

Orenda PR10000 Phosphate Remover @ Amazon

The Orenda PR-10000 which can be purchased for $46 per quart* or $135 per gallon* is very concentrated (70% lanthanum chloride by weight) where one quart removes 10,000 ppb phosphate in 10,000 gallons.

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Admin update: on 8/8/2014, with shipping added, the cost @ Epooldepot.com was $52/qt or $141/gal. This is still the best price I've seen online.

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It looks like that product may well be cheaper. I seem to remember the prices being higher in the past; am I mistaken about that?

I looked up some of your posts on that product. You note that it produced severe cloudiness, which is what happened to me, when I tested one of the first products nearly 20 years ago. Does using the clarifier simultaneously prevent that? The product I used years ago also plugged the sand filter, and I had a hard time backwashing and clearing it. Did you notice any similar effects.

I'm not sure why, but the Kem-Tek product produced no cloudiness when I used it. I even tried pouring it in a column in the deep end, so I could see the cloudiness better, and never did. I did not notice any effect on the filter or pressure. On a 200,000 gallon pool, it took a total of 26 quarts to read PO4 > 125 ppb. The largest single dose I added was 8 quarts.

Some phosphate remover products contain a clarifier in them so that may be the case with Kem-Tek. I believe that the Natural Chemistry Phos-Free products have clarifier.

Yes, using a clarifier should prevent or at least limit the time for any cloudiness. My pool cleared up very quickly once I added the clarifier and ran the filter 24/7. It was clear the next day, but I don't know when in that roughly 15 hours it actually cleared up (i.e. how long it actually took). Basically, the lanthanum chloride not only combines with phosphate in the water to form lanthanum phosphate but it also combines with carbonate to form lanthanum carbonate. This usually gets caught in the filter and if there is any additional phosphate then then carbonate is exchanged for the phosphate.

I did not notice any rise in filter pressure and I have a cartridge filter, but it's oversized 4-cart 340 square foot total area for a 16,000 gallon pool. When I cleaned the filter, I didn't notice any unusual amount of plugging up. It has the normal mixture of mostly suntan lotion along with cedar needles.

I'm not sure the more recent products have the severe side-effects I experienced, which has been limited to whatever product I used on that pool many years ago, and the Kem-Tek.

But it did surprise that I did not see any cloudiness -- even briefly -- from the Kem-Tek product. Initially, it made me afraid the product wasn't even working, so I was careful to do pre / post PO4 testing to reassure myself.

I should note that the product itself is a milky mixture, maybe like a water/skim milk mix. So when I poured it in, there was some haze from the unmixed product. But that disappeared as the product was diluted.