TTC/TTC vs. TTC/MALT Dipslides: What’s the Difference?
Microbiological dipslides are a simple field-screening tool for tracking microbial activity in industrial water systems. Cooling-tower and closed-loop monitoring programs may use them to follow trends where the selected method is appropriate. For water treatment bacterial testing, the choice between TTC/TTC and TTC/MALT starts with what you need to monitor.
What is a TTC/TTC dipslide?
A TTC/TTC dipslide has bacterial growth medium on both sides. It is typically used for general aerobic bacterial screening, often described as total viable count (TVC). The result estimates growth under the test conditions; it is not a count of every microorganism present or a species identification.
What is a TTC/MALT dipslide?
A TTC/MALT dipslide combines a TTC bacterial-growth side with a malt-based side intended to support yeast and mold growth. Yeasts and molds are fungi. This format provides a bacterial screening result alongside an additional view of fungal growth. Media formulations vary, so check the specific manufacturer's instructions.
The key difference
TTC/TTC focuses primarily on general bacterial monitoring. TTC/MALT adds yeast/mold screening to bacterial monitoring. The malt side broadens the screening scope; it does not identify a particular organism.
When might each be used?
- TTC/TTC: routine bacterial trend monitoring, including cooling-tower programs and closed-loop or other industrial-water systems where general bacterial activity is the main concern and the monitoring plan specifies this method.
- TTC/MALT: programs that need bacterial monitoring plus visibility into yeast or mold. It may be considered when recurring slime, organic fouling, or broader microbiological concerns warrant additional screening.
A dipslide result does not establish the cause of fouling. Investigate unusual results within the site's monitoring program and obtain laboratory support where needed. For meaningful comparisons, use consistent sampling and follow the selected product's handling, incubation, reading, and disposal instructions. Do not assume that incubation conditions are interchangeable between media.
Are dipslides a replacement for laboratory microbiology?
No. Dipslides support screening and trend monitoring. They do not replace laboratory analysis where species identification, regulatory testing, Legionella testing, or higher-precision microbiology is required. TTC/TTC and TTC/MALT dipslides do not identify Legionella or demonstrate regulatory compliance. A low general bacterial reading does not establish that Legionella is absent.
Practical selection summary
| Feature | TTC/TTC | TTC/MALT |
|---|---|---|
| General bacterial monitoring | Yes | Yes |
| Yeast/mold monitoring | Not specifically targeted; limited | Yes, on the malt side |
| Routine trend monitoring | Yes | Yes |
| Broader microbiological screening | More limited | Better suited when yeast/mold screening is also needed |
For cooling tower dipslides and other industrial applications, select the media to match the monitoring objective rather than treating either format as a universal test.
Need help choosing?
Tell us what your monitoring program needs to screen for, or share the dipslide type you currently use.
Need Help Choosing a Dipslide?
Technical references
- Lovibond D002 TTC/MALT technical datasheet — bacterial and fungal media.
- Lovibond general catalog, dipslides section — TTC/TTC and TTC/MALT screening scope.
- HSE HSG274 Part 1, paragraphs 1.126–1.131 — cooling-system dipslide monitoring and laboratory testing distinctions.