GUERNEVILLE, Calif. - Mid- and late summer is the time when algae blooms appear, bringing the threat of toxicity to families hoping to enjoy the water. 

That's going on right now in Sonoma County, where there are good algae and toxic algae. 

It's important to know the difference as the summer gets hotter and the algae blooms get bigger. 

Warning signs are posted along the Russian River at 10 beaches. They warn about potentially toxic algae sighted from near Healdsburg to the lower Russian River. 

The algae, which can spread toxins into the water, is usually found in floating patches called mats, of brown, orange, olive or dark red. It can also get stranded on rocks or on the bottom spread toxic into the water. It can be particularly harmful to small children and dogs.

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