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Based on the patented copper polyacrylate technology (1) that gave rise to MSA II algaecide, BioGuard has released two long-term algae inhibitors, Back-Up II and Salt Pool Protector. Both are highly concentrated and effective in halting the growth of most types of algae (excluding the copper- and chlorine-resistant phytoflagellate Chlamydomonas and the bacterial pink slime), yet are formulated to guard against instances of water discolouration, pool surface staining and "green hair" so often encountered with copper-based algae preventatives.


Some Frequently Asked Questions


1. Is there a difference between Back-Up II and Salt Pool Protector?


In a word, no. However, marketing surveys have shown that many salt pool owners are reluctant to buy products that they perceive, rightly or wrongly, are suitable only for freshwater pools. As such, it was decided to market the copper-based algae inhibitor formulation in two guises, Back-Up II for freshwater pools and Protector for saltchlorinated pools. Being a Class 8 Corrosive, Back-Up II can be displayed with algaecidal products like MSA II, Polygard and Algizine, whilst Protector can be displayed alongside Salt Cell Cleaner, Salt Pool Stain & Scale Control and Salt Pool Stabiliser.


2. How do Back-Up II and Salt Pool Protector differ from MSA II?


Although similar, the formulations are definitely NOT the same. The most important difference lies in the inclusion of a high molecular weight polyacrylic acid in the two algae inhibitors that provides far longer term stain protection than is possible with the MSA II formulation. Field trials performed prior to the release of Back-Up II and Salt Pool Protector showed that the anti-staining capabilities of the formulation persist for at least 6 months. Even though tightly bound to the polyacrylic acid, the copper remained active against algae over the entire trial period. Copper levels are comparable to those in MSA II (42 g/L in Back-Up II and Salt Pool Protector versus 40 g/L in MSA II) to ensure that copper residuals remain around 0.5 ppm, even with splash out and dilution due to heavy rain.


3. Why is Back-Up being superseded?


In recent changes to the Poisons Act in Australia, products containing more than 10% (w/w) benzalkonium chloride were rescheduled from S5 to S6. (2) The higher classification entails substantial changes to packaging, whilst raising concerns about the toxicity of the compound in its undiluted form. Bio-Lab was thus faced with two options. The first was to dilute Back-Up from its 40% active status to a mere 10% in order to retain the S5 classification. This would have necessitated consumers purchasing 4 litres of product, instead of 1 litre, to do the same job. The second was to build upon the success of the patented polyacrylate technology used in MSA II and develop a copper-based algae inhibitor that would remain active for at least 6 months without staining. Needless to say, Bio-Lab chose the second option. After extensive research, development and field testing at Bio-Lab in Canada and the US, Back-Up II was the result.


4. What effect do metal ions have on Back-Up II and Salt Pool Protector?


Ideally, there should be no pre-existing metals (copper, iron, manganese) in the swimming pool at the time of initial treatment. The recommended procedure (see below) includes pretreatment with Quick Clear and Pool Magnet or Salt Pool Stain & Scale Control to remove such contaminants. If small quantities (less than 1 ppm) of copper or iron enter the water from other sources (eg. pool salt, corroding heat exchangers or pool equipment) after treatment with Back-Up II or Salt Pool Protector, then excess polyacrylate present in the formulation will effectively bind with those metals and prevent them from staining pool surfaces. However, Back-Up II and Salt Pool Protector should NEVER be used in lieu of a stain and scale preventative.


5. Are Back-Up II and Salt Pool Protector effective against swimming insects or ducks?


Using Back-Up has two side benefits completely unrelated to inhibiting algal growth. The first lies in the product's ability to kill off swimming insects (referred to variously as "swimmers" and "boatmen"). The second lies in its ability to deter ducks from landing on pool water. Both benefits stem from the fact that benzalkonium chloride is a surfactant (surface-active agent) which changes the surface tension of the water. This not only disrupts the protective air "sheath" around swimmers and boatmen, effectively drowning them, it also makes ducks uncomfortable when their down comes into contact with water treated with Back-Up. Back-Up II and Salt Pool Protector do NOT contain benzalkonium chloride or any other surfactant, so have little impact on swimming insects and ducks. If an alternative to Back-Up is sought for these specific purposes, Polygard is advised.


6. How can pink slime be treated?


Again, Polygard can be used in the absence of Back-Up.


Specific Features and Benefits of Back-Up II and Salt Pool Protector Algae Inhibitors

Initial and Preventative Maintenance in Pools

Initial Dosage: 50 mL of Back-Up II or Salt Pool Protector per 10,000 litres.

Monthly Maintenance Dosage: 40 mL of Back-Up II or Salt Pool Protector per 10,000 litres.



1. If pool water tests positive for copper, iron or manganese, pre-treat with Pool Magnet for freshwater pools, or Salt Pool Stain & Scale Control for salt-chlorinated pools, as per directions.

2. To remove metals completely from pool water, add Quick Clear to pool filter. Do NOT commence treatment with Back-Up II or Salt Pool Protector until tests show metal residual to be zero.

3. With pump and filter running, dilute recommended dosage of Back-Up II or Salt Pool Protector in at least 4 litres of water, then pour around edges of pool near areas of greatest circulation.

4. Allow water to circulate for at least 2 to 4 hours following application.

5. To remove algae nutrients from the water, regularly oxidise using BioGuard Burn Out 35 or Lite.



1. J.P. Garris, US Patent 5,541,150 (Dated 30 July, 1996).

2. Australian Health Ministers' Advisory Council, "Standard for the Uniform Scheduling of Drugs and Poisons", No. 14, Amendment No. 1 (Effective Date - 18 December, 1999).


The above information is supplied by Bio-Lab and represents its best interpretation of available technical information at the time of preparation. The sole purpose is to supply factual information to Bio-Lab customers. It is not to be taken out of context nor used as support for any other claim not made herein.