These are five tanks for the filtration system for the new olympic size pool. The photo is from the Town Crier, Wednesday, November 12, 1958.

The text reads:

"Rolling Slowly up Main Street come these five tanks recently, causing a rush to the zoning lawbooks to see if heavy industry was coming to Los Altos. The tanks, as it turned out, house the filters for the new Olympic-sized swimming pool at the Fremont Hills Country Club. Each is nine feet in diameter, will handle the pool's 426,000 gallons in a cycle less than eight hours. And, if you coax them enough, Fremont Hills Club members will admit there's a chance the 1959 National Outdoor Men's Swimming and Diving Championships may be held here next July."