What a maker states, and for what purpose
One thing, exactly: the quantity of a given product a manufacturer states for a given volume of water, for a named purpose. Routine chlorination and shock treatment are two different doses of the same product, and a listing that gives only one figure has given only half the instruction.
It fixes it usefully, because it is the only figure on the chemical shelf that connects a product to a pool at all. Everything else — active content, concentration, pack size — describes the tub.
Why it is not transferable between products
It does not promise a result. Dosing a pool is a process with feedback: you add, you wait, you test. A published dose is the starting point of that process, not its outcome.
It does not promise transferability. A dose stated for one product cannot be applied to another of the same family, because the concentrations differ. This is the most consequential misreading on the shelf and the reason the concentration is always printed next to the dose here.
And it does not promise safety. A dose is a figure; a chemical still has handling requirements, incompatibilities and a safety data sheet, and those belong to the manufacturer rather than to any comparison page.
What has to be printed next to a dose
Concentration or active content, without which a dose is uninterpretable. The purpose the dose was stated for — routine, shock, start-up, winterising — because the same product carries several. Contact time, on flocculants, where the instruction includes waiting and often vacuuming to waste. And temperature and volume limits on active oxygen, which several makers state and which are part of the instruction rather than a footnote to it.
Every chemical family, without exception
Every chemical family without exception: tablets, granules, bromine, active oxygen, algaecide, flocculant, pH correctors, winterising products and pool salt — where the figure is a target salinity rather than a dose, which is the same principle inverted.
The site repeats one sentence on every page that carries a dose, rather than stating it once here and assuming it: a dose is a published figure about a product, and it is never presented on this site as advice about what a particular pool needs.
What readers keep writing in to ask
Why convert everything to cubic metres?
Because a capful and a scoop cannot be compared, and because the volume figures pools are sold on are in litres or cubic metres already. Converting the unit is arithmetic on the maker’s own number and changes nothing about it; the page says when it has done so.
Can I just multiply the dose by my pool’s stated volume?
That is a question for the instructions on the product, not for this site — and a stated volume is not the water a pool holds. What the page gives you is the maker’s figure and the unit it was published in, so that you are working from the manufacturer rather than from us.
Why do two algaecides differ tenfold in dose?
Because concentration differs. A 10 % product and a 60 % product are dosed accordingly, and the dose alone is meaningless without the concentration beside it. Pages here print the two together, which is why the cheaper bottle is frequently the more expensive purchase.
Does the site ever say how much to add?
No. It reports the dose each maker states, brings it to a common unit so it can be compared, and stops. What a particular pool needs on a particular day depends on bathers, sunlight, rainfall and what is already dissolved in it, and none of that is published by anybody.
Last reviewed 21 September 2026