Direct answer: both approvals are required
Do not use the skimmer as a shortcut without explicit permission from the exact sanitizer label and applicable equipment instructions. Pump runtime is not permission, and an equipment change requires a new check. The Rainbow 320 fit/approval record covers a separate dedicated-feeder decision. Storage conditions and local disposal arrangements remain separate safety tasks.
Pool-chemical safety: Follow the product label. The CDC pool-chemical guidance says to keep each chemical in its original labeled container, store chemicals separately in a dry, well-ventilated area, and never mix chlorine with acids or different chlorine products.
Use a dedicated feeder or floater by default. Put a tablet in a skimmer only when the exact sanitizer label and the pool equipment manufacturer explicitly permit it. Without both approvals, the shortcut is not worth the equipment risk.
A pump timer does not supply the missing approval
The relevant question is not whether the pump normally runs for eight, twelve or twenty-four hours. A timer can change, a breaker can trip and equipment can stop unexpectedly. If the tablet label or any connected equipment manual prohibits skimmer dosing, a longer run schedule does not override that prohibition.
For an existing installation, make a simple chain of the water path: skimmer, pump, filter, heater and any other connected equipment. Identify the exact manual for each component. An approval for a tablet’s application method does not establish that every downstream component tolerates that route.
Keep the approval record with the maintenance instructions and revisit it whenever a heater, pump or sanitizer product changes. If one component is unidentified, do not infer permission from the others. Choose a properly approved dosing arrangement after resolving that gap.
If tablets are already being used by a prohibited route, follow the product and equipment manufacturers’ instructions for stopping and correcting the arrangement. Do not casually retrieve wet tablets, return them to dry stock or move them to a device containing another product.
Why the skimmer can be a problem
A trichlor tablet dissolving in the skimmer creates highly chlorinated, acidic water close to the suction plumbing. While the pump runs, that water moves through the circulation system. When the pump stops, concentrated water can remain near the skimmer, pipe, pump, filter, or heater instead of dispersing through the pool. Other tablet chemistries have different properties and may be incompatible with trichlor residue or the same equipment.
The risk depends on the tablet chemistry, pump schedule, plumbing, equipment materials, and manufacturer instructions. For example, the current In The Swim 3-inch trichlor instructions say not to place those tablets in the pool or skimmer and direct users to a floater or automatic feeder. Pentair’s MiniMax Plus HP manual likewise warns against chemicals or chlorine tablets in the skimmer. Check the exact sanitizer and equipment instructions because another product or system may impose different conditions.
The decision rule
- Read the tablet’s current product label.
- Read the skimmer, pump, filter, and heater instructions. If flow is already weak or the filter gauge has fallen from its baseline, diagnose that condition with the flow-and-pressure decision map before relying on the skimmer path.
- If either source does not authorize skimmer dosing, use a dedicated device.
- If both authorize it, follow every condition, including circulation requirements and tablet format.
- Test free chlorine and pH; do not estimate output from how quickly the tablet shrinks.
Better options
Floating dispenser
A floater is inexpensive and requires no plumbing. It keeps the tablet out of the suction line, but it must be compatible with the tablet and kept from resting against a liner, wall, ladder, or step.
Inline feeder
An inline feeder belongs in planned return plumbing and keeps tablet handling at the equipment pad. It requires correct placement, service access, and professional installation when plumbing or electrical work is outside your experience.
Off-line feeder
An off-line feeder uses bypass tubing and can suit a retrofit where the main line should not be cut. Tubing, fittings, valves, and seals add maintenance points.
Never do these things
- Never place loose tablets directly on a pool surface.
- Never mix tablet chemistries or load a feeder over unknown residue.
- Never use a skimmer tablet as a substitute for water testing.
- Never leave a known incompatible tablet in the basket because the pump will run “most of the day.”
- Never handle wet or contaminated tablets with bare hands.
Default to a Dedicated Feeder
The safest general answer is no: do not use the skimmer as a tablet feeder unless the sanitizer label and every relevant equipment instruction explicitly say you can. A compatible floater or dedicated feeder gives the chlorine its own controlled device and avoids turning the suction system into an improvised chlorinator.