In the Swim sells pool and spa supplies — chemicals, test kits, equipment and parts. Most of what goes wrong with a pool is water chemistry, and most wasted money on pool supplies is chemicals added without testing. This In the Swim guide is about buying the right things in the right order.
Buy a proper test kit first
Test strips from In the Swim or anywhere else are quick but imprecise. A drop-based test kit gives far more reliable readings, especially for free chlorine and cyanuric acid.
In the Swim sells both. If you manage your own pool, the drop kit pays for itself by stopping you adding chemicals you did not need.
Test at least weekly, and after heavy use, heavy rain or a heat wave.
The ranges to aim for
Commonly used targets for a residential chlorine pool:
Free chlorine: enough to sanitise, which depends on your stabiliser level — higher stabiliser needs higher chlorine.
pH: roughly 7.2 to 7.8. Outside this, chlorine works poorly and swimmers' eyes sting.
Total alkalinity: roughly 80 to 120 ppm. It buffers pH against swings.
Cyanuric acid (stabiliser): typically around 30 to 50 ppm for an outdoor pool. It protects chlorine from sunlight, but too much makes chlorine sluggish.
Calcium hardness: roughly 200 to 400 ppm for plaster pools. Too low etches surfaces; too high causes scale.
Adjust alkalinity before pH, and pH before chlorine.
Choosing a chlorine type
In the Swim sells chlorine in several forms, and each changes your water differently.
Trichlor tablets are convenient in a floater or feeder, but add stabiliser every time and lower pH. Over a season, stabiliser climbs.
Liquid chlorine adds nothing but chlorine and salt. It is heavy to carry and degrades in storage, but it gives the most control.
Cal-hypo shock adds calcium. Fine where water is soft; unhelpful where it is already hard.
If your stabiliser keeps rising, switch from tablets to liquid chlorine for a while rather than draining.
Buying in bulk
Pool chemicals are cheaper per pound in larger containers, and In the Swim prices reward buying for the season.
Bulk works for stable products — tablets, pH adjusters, alkalinity increaser. It does not suit liquid chlorine, which loses strength over weeks, especially in heat.
Store chemicals cool, dry and apart. Never store chlorine products near acids, and never mix different chlorine types.
Parts and equipment: match the model number
In the Swim sells replacement parts for pumps, filters, heaters and cleaners, and the only safe way to order one is by the model number on your equipment.
A filter cartridge that looks identical can differ in length, diameter or the size of the centre hole. Photograph the label on your filter or pump before you open the In the Swim site, and search by that number rather than by appearance.
For a pump, check the horsepower, voltage and plumbing size against the old one. A more powerful pump is not automatically better; it can be too much for your filter and uses more electricity.
Opening and closing the pool
In the Swim sells seasonal opening and closing kits that bundle the chemicals for each job. They are convenient, but check the kit size against your pool volume before buying, and compare the kit with the items bought separately.
If you do not know your pool volume, work it out before buying anything. Every dose on an In the Swim label is given per volume of water, and a guess is how people overdose.
Shipping heavy chemicals
Pool chemicals are heavy and some are classed as hazardous for shipping, which can limit how and where In the Swim can send them. Check the delivery options and any restrictions on the product page before building a large order.
Open chemical deliveries outdoors and move them straight to storage. Never leave a damaged container of chlorine or acid in a garage with other products.
Where the In the Swim savings are
In the Swim percentage codes often exclude some equipment brands. The dollar codes usually need a minimum order — combine the season's chemicals into one order to reach it.
Early-season and end-of-season In the Swim sales are the time to stock up on stable chemicals.
Use the 25% In the Swim code on a large chemical order and the $20 code when your basket is smaller but still meets its minimum. Check which products each code excludes before you rely on it.
In the Swim normally accepts one code per order. Put the whole season's stable chemicals in one basket and apply your best code once, rather than splitting orders and paying shipping twice.
Common questions
Why is my pool cloudy?
Usually low chlorine, high pH or poor filtration. Test before adding anything.
Why does my chlorine keep disappearing?
Low stabiliser in sunlight, or a high organic load. Check cyanuric acid first.
Are test strips good enough?
For a quick check. For adjusting chemistry, a drop test kit is far more reliable.
How do I find the right filter cartridge at In the Swim?
Search by the model number printed on your filter housing, then check the length and diameter before ordering.
| Discount | Type | Get the deal |
|---|---|---|
| $5 off | Promo code | View at In the Swim → |
| $5 off | Promo code | View at In the Swim → |
| 50% off | Promo code | View at In the Swim → |
| 10% off | Promo code | View at In the Swim → |