- Ensure biocide pumps/feeders are operational.
- Confirm the drum or feeder is not empty.
- Check that the feed rate aligns with recent water usage.
- Ask the customer:
- Was the cooling tower cleaned before startup this season?
- If it's a year-round system, was it cleaned in the last 6 months?
- If it hasn’t been cleaned recently, biocides may be ineffective due to accumulated sediment or mud in the basin/sump.
- Manual removal (shoveling and hosing out) may be required before treatment can work.
- Determine if the treatment program has been maintained consistently.
- Systems left untreated build up organic debris that biocides alone can’t handle.
- Observation tips:
- Is the water hazy?
- Is foam dirty or excessive?
- Are surfaces slimy to the touch?
Consider recleaning systems with poor treatment history or visible grime.
- Algae may grow in:
- Areas with low/no water flow
- Spots with splashed water or mist
- These areas may not receive effective biocide exposure.
- If algae grows where sunlight hits, try to block the light.
- If that’s not possible, inform the customer it's a cosmetic issue needing mechanical cleaning.
- It likely originates elsewhere and breaks off/migrates.
- Upgrade filtration to capture mobile algae moving through the system.
If algae is found in areas with good flow and fresh treatment, investigate further:
- Add a non-oxidizing biocide or algicide for broader control.
Check dose levels and frequency:
- For slug/intermittent feeding (manual, timers):
- Follow label instructions carefully.
- Increase dose within label limits.
- Break large doses into smaller, frequent doses for better efficacy.
- For continuous feed (proportional to makeup water):
- Verify halogen levels are in range.
- Perform microbiological testing (ATP, dipslides, cultures).
- If tests are out of range, increase dose per label guidelines.
If all the following are true:
- System has been cleaned
- Biocides are present and properly dosed
- Dual biocide program is in use
- Treatment levels and bacteria tests are in range
- Algae is not cosmetic and still persists
👉 Flag the system for management or technical support review — a deeper issue may be present.
- Clean the system thoroughly.
- Confirm biocide is being fed correctly.
- Use both oxidizing and non-oxidizing biocides where appropriate.
- Adjust doses and feed frequencies.
- Observe, test, and escalate as needed.