Methodology

What we have not done

Units we claim to have tested: 0. Sponsored placements accepted: 0. Free products accepted: 0.

Everyone in this category says they tested twenty robots. We have not tested any, and we say so on every page. Skim & Soak launched in 2026. There is no test pool here, no lab, no fleet of units in a garage and no thirty years in the trade. Anyone claiming otherwise on a site this new would be inviting you to check.

That is a real gap, and the obvious next question is why you should trust any of this. The answer is on the rest of this page, and it is not a credential - it is that everything here is reproducible. You can redo any calculation on this site and get our answer, or find that we got it wrong, which is a thing a testing anecdote can never offer you.

Where every number comes from

Doses on this site are computed rather than remembered. There are exactly two inputs, and you can check both:

1. The active-ingredient percentage printed on the product you own. 68% cal-hypo, 56% dichlor, 90% trichlor, 12.5% trade liquid chlorine, 100% sodium bicarbonate. This is on the bag or bottle in front of you.
2. The weight of water. 8.345 lb per US gallon, which is physics rather than a pool-industry convention.

Everything else follows. That is why the generic advice - “one pound per 10,000 gallons” - is wrong for most pools and most products: it silently assumes one volume and one percentage, and changing either makes it wrong, sometimes by a factor of four.

Chlorine, granular

lb = (ppm x gallons x 8.345) / (1,000,000 x available-chlorine fraction)

Worked, for a 10 ppm shock in a 15,000-gallon pool with a 68% cal-hypo: (10 x 15,000 x 8.345) / (1,000,000 x 0.68) = 1.84 lb

Chlorine, liquid

Trade percent is grams of available chlorine per 100 mL, so 12.5% liquid chlorine carries 125 g/L and one US gallon carries 473 g. Raising 10,000 gallons by 1 ppm needs 0.08345 lb, which is 37.85 g. One gallon of 12.5% therefore moves 10,000 gallons by 12.5 ppm - which is why the shorthand works at that one volume and nowhere else.

gallons = (ppm x pool gallons) / (trade % x 10,000)

Worked, same pool and same target: (10 x 15,000) / (12.5 x 10,000) = 1.2 gal

Total alkalinity

Alkalinity is reported as calcium carbonate equivalent. One mole of sodium bicarbonate (84.007 g) is one equivalent, and one equivalent of calcium carbonate is 50.04 g.

Worked, for +10 ppm in 10,000 gallons: 10,000 gal = 37,854 L; ((37,854 x 10) / 1000) / 50.04 x 84.007 = 635 g = 1.4 lb

That is where the “1.4 lb per 10 ppm per 10,000 gallons” figure repeated all over the internet actually comes from. We show the derivation because it is the only way to know it scales correctly to your pool.

Cyanuric acid

Dosed as a straight concentration, so the water-weight constant is the entire calculation. Worked, for +30 ppm in 15,000 gallons: (30 x 15,000 x 8.345) / 1,000,000 = 3.76 lb

What we do not compute

pH reduction. How much acid a pool needs to move pH depends on its total alkalinity, not on its volume alone, so no honest general formula exists. That is exactly what an acid demand test measures, and it is why this site publishes no pH-down dose table and recommends a kit that includes one instead. Anyone printing a general table for this is telling you a number that is wrong for most pools.

The source hierarchy

A dose may rest on one of these, in this order. A figure that fits none of them is not published - the page says “check your label” and prints no number at all.

1. The manufacturer’s own product page, label or SDS for the specific product recommended, linked.
2. A published standard - the CDC Model Aquatic Health Code, or the ANSI-accredited PHTA standards.
3. A government reference that quotes those standards.
4. Our own arithmetic, shown in full so it can be checked.

Never acceptable: a dose recalled from memory, a dose copied from another article, or any figure presented without its source.

One note on the CDC

The CDC’s Healthy Swimming pages returned an HTTP 403 to every request from our systems, so we have not cited them directly - citing a page we could not read would be exactly the shortcut this site exists to avoid. Where MAHC parameters appear on this site they are cited through Michigan EGLE’s guidance for licensed pools, a state document that quotes MAHC 5.7.3.1.1.5.0 directly and that we did read.

Why the label always wins

This is not a disclaimer, it is the legal position. That same Michigan guidance sets out the chain: under the EPA FIFRA rule, the maximum free chlorine concentration is dictated by the manufacturer’s instructions for use, and applications must not exceed the limits specified on the product label. The state notes that many pool chlorine products carry an NSF-listed maximum application rate of 10 ppm.

So every dose table on this site is a calculation you check against your own bottle. If our number and your label disagree, your label is correct and we would like to hear about it.

How we pick products

Every pick on this site is chosen on a published specification that we can name, and every one is written up with the same four things:

• The published figure it turns on. An available-chlorine percentage, a coverage area per cycle, a filtration micron rating, a mesh aperture. If a product publishes nothing checkable, that is itself a finding and we say so.
• What the number means for your pool, worked through rather than asserted.
• What it costs you - not just money. Cal-hypo adds calcium; dichlor adds stabilizer; a fine filter needs cleaning more often. Every choice has a downstream consequence and we name it.
• Who it is wrong for. Every one of the 71 products in our registry carries a “skip it if” line - 71 of 71, because the data model makes it mandatory. A roundup where nothing is ever wrong for anyone is not a recommendation.

Where the products came from

Product identifiers and specifications were read from live Amazon listings and manufacturer product pages on 2 September 2026. Nothing here was recalled from memory or carried over from another site. Where a listing could not be resolved, the product carries no identifier and its link falls back to a tagged Amazon search - a link that still works and cannot land on a dead page.

How prices work

Prices on this site come from one place: a live price layer refreshed on a schedule. There is no price typed into any page, and no field in our content model that could hold one.

If that layer has nothing fresh for a product, the button reads “Check price on Amazon”. That is a first-class state rather than a failure - it is what honest looks like when we do not currently know. A price older than 48 hours is treated as unknown and disappears on its own rather than sitting there being wrong.

Right now, that is every button on the site. The price layer has not yet run against a live retail data feed, so nothing here shows a number. When it does, prices appear with the date they were checked printed beside them.

How we make money

Skim & Soak participates in the Amazon Services LLC Associates Program. When you buy through a link here we earn a commission, at no extra cost to you. That is the whole business model.

It does not change the picks, and there is a checkable reason to believe that beyond our saying so: every roundup on this site names at least one product we would skip and explains why, and several pages recommend the cheapest possible answer - a two-dollar net, a bag of baking soda, cutting back a tree branch - over anything expensive. The full disclosure sets out the rest.

What this site covers, and what it does not

• We cover residential pool water problems, the chemistry that fixes them, and the equipment that prevents them.
• We do not cover pool construction, resurfacing, or anything involving gas, high-voltage electrical work or structural repair. Those need a licensed professional and we are not one.
• We do not recommend local services. We have no way to assess a contractor in your area, and pretending otherwise would be the easiest possible way to be useless to you.

How to tell us we are wrong

Email through the contact page. If you can, include the page, the figure you think is wrong, and what you believe the correct value is - a link to a label or a standard is ideal.

Corrections get made, and every page carries a last-reviewed date so you can see when it was last looked at. Our full correction policy is on the editorial policy page.

All 47 content pages on this site are written by Scooter M..