Where do you live?

Are you saying the KBG grows fast even without irrigation?

Generally fescue and rye are bunch grasses. KBG is a sod forming grass like zoysia, creeping bentgrass, bermuda, and St Augustine. The dwarf type fescues, like Marathon I, II, or III grow so slowly they seem like then don't grow. They might not be available in your area, but other dwarf fescues should be.

I live in New Jersey in a flat plain area with loam soil and woods. In spring and fall the grass grows extremely fast. If its raining during the summer the grass is growing. The seed mix I tried was

29.5% Dakota truf type Tall Fescue

19.65% Montana Tall fescue

14.75% Frontier perennial ryegrass

14.75% Madison kentucky bluegrass

9.82% Singular Perennial ryegrass

9.80% Hood chewings fescue.

.02% weed seed

.04% other crop seed

1.67% inert matter

Based on the description and pictures it looks like montana tall fescue is the one growing so tall. Im wondering if perennial rye or a different fescue would grow slower than this blend to cut mowing down to every 2 weeks or more. I will look into the other dwarf fescues

too well actually because it grows so fast it should be mown every 5 days

That's normal for this time of year. If you want to cut less there's growth regulators like T-Nex which would cut down on your mowing by up to 50%.