First off, if you were watering it twice a day, I would not be supprised if you had a soil fungus. Thats a bit wet for not being summer, unless you just sodded your yard.

Your 2x a week should be good.

9 zones on a 1/4 acre is alot. I have 3 zones on a half acre. On our reclaimed water, low pressure homes (30-40psi) the standard is 2-3 zones on a 1/4.
I would do some repiping and get your yard on 3 or so zones. Then water 2x a week at 45 min to a zone or so.

Is Scotts southern Turf builder the stuff with atrazine in it? I would just use regular fert till you get the lawn grown in, then worry about the weeds. (Atrazine is a weed killer).

That is my 2c to you.

FWIW, living in Houston and when getting normal rainfall, I rarely water the grass. If taking care of the lawn correctly you should be able to at least go a week between watering. I've gone years without watering the yard. Part of it will depend on your soil quality. Since you have a new home I would guess it is poor. The first couple of things I would do.
1) Cut the grass as high as your mower will go
2) Only water when the grass starts to wilt and then water deeply. That means 1 inch of water. You will need to put out a tuna can to catch the water to measure. Since your soil is probably poor you will have to rotate zones to give it a chance to absorb the water or it will start to run off. The crunchy feeling you are getting now is from the dead grass left over from the colder than normal winter.
3) I use organic methods mostly so that part is up to you. At the very least I don't suggest using any weed and feed or insect killer over the whole yard. A basic fertilizer should be fine (slow release is even better). Spot treat weeds insects if necessary rather than doing the whole yard.

Here is a link that might be useful: Organic FAQ

Ltruett is correct. If the soil is in good shape, you can go a long time between watering. Frequent usage of herbicide, pesticide, fungicide, etc can ruin soil where soil can't hold water long enough or where water can't penetrate soil deeply without earthworms (pesticide can kill them) doing all the aerating in the ground so spot weed or harmful killing is better.

You need to wean the grass from frequent watering. 2x per week is too much for Houston. You can do that in certain parts of the Sahara desert but Houston gets 60+ inches of rain per year. That is far too much moisture to water 2x per week. And as your neighbor, ltruett, said, mow at the mower's highest setting. There is never any reason to mow St Aug lower...unless your wife tells you to ;-)

I made a mistake in the initial post. The lot is 1/2 acre. I'd estimate 9k-10k sq ft of actual grass. There are 10 zones on the sprinkler system due to fences, etc.

I've measured the output on a few zones and adjusted the system to run 45-65 minutes per zone once per week starting at 2:15am. I set the rain sensor to 1". I'll mow it at the highest settings (apparently 3.5") and we'll see what happens.

I also might apply some more of that southern turf builder (30% nitrogen) in a month or 2 if the grass is not taking off. I did a PH test on this soil and got 7.5. It is mostly clay. This soil might need lots of help until the lawn is established.

Thanks for the tips.

Okay but watch the grass until the roots grow deeper. It needs to be weaned, not cold turkey. If it needs water before the timer goes off, water it. But try to stretch. That will force the roots down into the moist soil.

Your pH is normal for Houston. I would not worry about that yet. Lets get the grass up tall and watered right first. The best thing you can do for the soil is stop using chemicals and start using organic fertilizers. ltruett can help you find them in Houston. If you want to go that direction, start now. If you want to continue with Scott's, then wait until the grass can go a full week without watering before fertilizing again. When you fertilize with Scott's, be sure the sprinkler comes on to water it in. You don't need to do that with organic.

It seems to have made it a week w/o needing water this week, but it was not extremely hot/sunny. I'm actually interested in going the organic route, but I need to read up on what to do/buy. I'm actually west of Houston in Katy, and would need to locate the the stuff.

I would also watch for excessive runoff. The clay soil might not absorb the water quickly so you might have to water for 20-30 min at a time and rotate. This time of year you really shouldn't need to water your lawn. In the heat of the summer last year when it didn't rain for 6 weeks I watered once a week. Once it started raining towards the end of the summer I haven't watered the yard since.

To find organic fertilizers I would just look for feed stores out in Katy. I did a quick google search of "feed store katy" and some popped up. Generally I look for soy bean meal or cotton seed meal. Alfalfa pellets work well. A one time compost tea application might benefit you too.

If you do go the organic route, you will just need a little patience the first year. When I moved into my current house last year I thought the yard was one of the worst, later than most greening up, weeds etc. By the time fall came it was greener than most before the hard freezes came and greened up earlier than most this spring.