Visual system Detection method Safety Positive reaction Negative sample Need to UV ray Stability Cross contamination Use time
magnesium Sulfate Visual Yes Turbidity No turbidity No 5-10 seconds No Before the amplification
Calcium chloride Visual Yes Turbidity No turbidity No 40-60 seconds No Before the amplification
SYBR® Premix Ex TaqTM II Visual Yes Green Red Yes 1–3 days Yes After   the amplification
Hydroxynaphthol blue Visua Yes Sky blue Violet No 2-3 weeks No Before the amplification
GeneFinderTM Visual Yes Green Red No 2-3 weeks No Before the amplification
SYBR Green I Visual Yes Green Red Yes 2-3 weeks No Before the amplification
Ethidium bromide Visual No Yellow No color Yes 2 weeks Yes After the amplification
Table 3: Comparison of colorimetric assays together.