Algaecide vs Shocking: Which Clears Algae?
Pool algaecide vs shocking compared: killing existing algae, prevention, chlorine demand, copper staining and what to do first.
The short version
Shock kills algae by overwhelming it with chlorine, which is what clears an existing bloom. Algaecide mainly prevents algae taking hold and helps where chlorine alone struggles. Shock to clear a bloom, and brush while you do it; use algaecide to prevent, particularly at the end of the season or before a spell away.
At a glance
| Polyquat 60 Algaecide | 18 in Heavy Duty Pool Brush | |
|---|---|---|
| Clears an existing bloom | Slowly | Not on its own |
| Prevents algae | Yes | No |
| Works without chlorine | Partly | No |
| Staining risk | Copper types can stain | None |
| Foaming | Some types foam | None |
| Essential during treatment | Helpful | Yes, brushing is critical |
Choose the Polyquat 60 Algaecide if…
You want to stop algae before it starts, especially closing for winter or leaving for a fortnight. Polyquat is preferred by many because it does not contain copper, which can stain surfaces and turn blonde hair green.
Check Polyquat 60 Algaecide on Amazon
Choose the 18 in Heavy Duty Pool Brush if…
Chemicals alone do not clear a bloom. Algae clings to surfaces where chlorine reaches it poorly, and brushing every surface before and during a shock is what actually exposes it. People who say shocking did not work usually did not brush.
Check 18 in Heavy Duty Pool Brush on Amazon
Related
Comparison based on published manufacturer specifications and the general consensus of owner reports. We have not tested these products side by side. Confirm current specifications and prices before buying. As an Amazon Associate we earn from qualifying purchases, at no extra cost to you.
Frequently Asked Questions
Why did my pool go green overnight?
Chlorine fell to zero, usually because stabiliser was too low so sunlight destroyed it, or because a heavy rain diluted everything. Green in a day means chlorine was absent, not low.
How much shock do I need?
It depends on volume and how bad the bloom is, and it is more than most people add. Our shock dose calculator sizes it, and under-shocking is why blooms come back within days.
Does algaecide replace chlorine?
No. It is a supplement, not a sanitiser. A pool with algaecide and no chlorine is not safe to swim in, whatever it looks like.
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