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Back to basics: Choosing the right clarifier

Treating with clarifiers

When pools are not equipped with skimmers, keeping the water clear will be quite difficult
When pools are not equipped with skimmers, keeping the water clear will be quite difficult

If it has been determined there are no apparent issues with water balance or equipment, a service tech should consider using a clarifying agent. There are many options available in the water clarifier category, and with so many to choose from, making a decision can be overwhelming. In many cases, pool care experts such as dealers or service technicians are expected to be able to resolve these issues as quickly as possible. Understanding the technologies and chemistries available can help pool experts make the most informed recommendation for each particular water quality issue.

Most pool chemical companies commonly offer clarifiers that may either be synthetic or ‘natural’ polymeric coagulants. These popular clarifiers are positively charged, or cationic. Most of the cloudy water causing particulates have negative, or anionic, charges. Chitosan or synthetic polymer-based clarifiers help bind the microscopic particles together so they can form one large chain that can be captured by the filter. These typically have smaller treatment doses and are often used more for maintenance purposes than as a troubleshooter. Dosages of 29.5 to 59 ml (1 to 2 oz) per 18,927 L (5000 gal) are the most common measurements one is likely to see. Polymeric clarifiers often require less physical maintenance than other methods may need and are good for pools that cannot be effectively vacuumed. These types of products often work best when the problem is observed early on. While effective and treatments are easy, some can take up to 48 hours to restore water clarity. Another drawback is that for some clarifiers, it is quite important for service techs not to over-apply the product. An overdose of a synthetic polymer can actually make a water-quality issue worse.

Maybe a flocculant is the right way to go

Flocculants, typically an aluminum-based material such as aluminum sulfate (alum) or poly-aluminum chloride, work by bridging together large amounts of particulate to help them drop to the bottom of the pool to be easily removed by the vacuum. Flocculants are often poured directly down the skimmer, which enables it to be distributed throughout the pool quicker. Some require minor adjustments to the water’s chemical balance to maximize efficiency.

Flocculants are often useful after an algaecide treatment, and to remove dirt particles that have been blown into the pool after a major storm. They are also ideal for use in pools that have poor circulation, as flocculants, in many cases, have a much quicker turnaround since they often work overnight. Although they do require a bit of legwork for consumers or service technicians, flocculants show results in just a few hours. The major drawback with these is they are dependent on the type of filter the pool owner has (e.g. those that are able to be vacuumed to waste such as sand or some DE filters). Vacuuming such a large amount of debris through the filter can overload the media and, in some cases, even damage cartridges. Since vacuuming to waste will require water replacement, a flocculant may not be the right strategy in areas or times where water usage is restricted.

When should one try filter media?

Sometimes, the filter media itself is not sufficient in grabbing tinier particles. While sand filters are common and perfectly fine to use, this media is not as efficient in capturing smaller particle sizes that cartridge or DE filters can.

In fact, cellulose and even DE can be highly efficient at clearing up a cloudy pool. Some cellulose products are modified to have a charge to enhance the ability of capturing particulate. These filtration aids are applied similarly to flocculants, down the skimmer to allow the product to form an additional layer atop the filter sand, DE, or cartridge. That said, a pool with at least one skimmer is critical to it working. These have a universal appeal, as they are not only useful in filtering out smaller organic debris, they can also capture surface staining metals such as copper, iron, or manganese. When these products are applied, they settle into a layer on top of the sand bed, providing another layer where debris can be captured. How much is applied depends on the square footage of the filter’s filtration area. If either DE or cellulose is added to aid a sand filter, thorough backwashing is required once the filter pressure rises significantly. It is important for service techs to always read and follow label directions for the product, as well as manufacturer’s directions for any equipment.

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