First AG day... unexpected results

Using a ten gallon Home Depot water cooler as our mash tun and pouring 170 degree water through a colander during our fly sparge every calculator has told us that we saw approx. 83 percent efficency. OUr temperature was maintained right at approx 149 degrees due to the insulation. I'm not sure that I buy our efficency being that high and are there any other ways we might be able to increase it? Thanks much for any assistance.

Add a mash-out with boiling water so the bed comes up to 165-168*F to thin the viscosity. Then use water hot enough to maintain the bed at between those temperatures throughout the sparge. You might need 180*F sparge water in the HLT. When Fly sparging, it isn't uncommon to see 88-90% eff.

OK great... Thank you very much for the feedback. The only concern we had about using such hot water is that we read in several places that it would leech tannins from the grains.