ok... first can I ask how often to you water and for how long, also what is the surface area your raised beds i.e. width x length (too me it looks too dry)
during summer where I live in Australia the summer weather gets very hot and dry, (I water my plants every day so that the soil is damp even at the surface)
also I think you may have some nutrient lock out due to the high ph in the soil and tap water you are using.
Our water is around 7.9. Compost and poop is needed in copius amounts.
You can add some white vinegar to the water. Test to see how much it takes per gallon to get the ph down to ~6.5 or so, and then add that much each time you water. There is also a product called PH Down (phosphoric acid) that you can use. Different water sources have different buffering capacities so there's no simple chart or formula to find out how much to add based on starting PH and volume, you'll have to experiment.
Your going to have problems with the maters unless you get some cages or something to contain and support them. They'll crowd out the peppers pretty quick when they're that close to them.
As far as your problem goes. I think it's your soil mix. It looks like it's to heavy and is compacting up not letting the roots breath. It will make them act just like they do when they are to wet, and the plants look just like that.
If the "Top soil" in your mix was the bagged kind from the stores, it is more like mulch than actual topsoil. At least all the brands I have tried have been. I add in Vermiculite, peat, local sandy dirt, and compost to any of the "Topsoil" I buy now. I also add Alfalfa and seaweed now and it really loosens things up.
Good luck with them, I hope you get it all sorted out. The one thing I've learned about gardening, is that you never stop learning.
I agree with the soil. it looks VERY compacted. When that happens, it is going to be very hard to let the roots breath and probably very hard to let the dirt get a point of being dry.
Throw in the fact the tap pH is 9 and that will raise the soil pH. I'd try the 'let the tap water sit in a giant bucket or clean fresh garbage can' idea for a few hours, and then test to see what that does. As already mentioned, experiment with vinegar to lower the pH of the water in the bucket if letting it rest doesn't help much. I've never had this problem, so I googled it and found something that might help
http://www.organicgardening.com/learn-and-grow/how-lower-your-soil-ph
If your concerned about pH..maybe get some pH down from amazon or whatever. From personal experience, vinegar really doesn't do much to lower the pH and it also creates a lot of salt buildup that will require an occasional flushing. Personally, my pH is around 8 and has been since day 1 and things are fine. I believe in nature and in nature, rain is not pH balanced and plants grow just fine, including peppers. I think sometime people (myself incluced) get way to over worried about the "perfect" scenerio for peppers and other plants. Nature is pretty smart...give it a try
I will say I have been growing peppers for many years and this is my first year growing in pots thanks to the advice from great folks on here. Growing in pots CERTAINLY has shown to be a better alternative than in the ground. My plants are bigger and healthier this season. I attribute this to being able to control moisture and nutrients myself. I have also been able to move them around and protect them when weather hits..unlike planting in the ground.
boy there is sure a change from the older leaves and newer ones
you may consider trying to improve your inground growing area before replanting it
the compost and other amendments can turn that stuff from a problem into a proud of
i think if you double dig the whole area down like 18 inches or so and start rebuilding the soil you
can have the envy of the neighborhood (as far as gardens go)the picture of the soil in hand looks really rich
and i bet it is really good stuff that just needs a little modification for good results
please consider the tilling of the soil as preliminary this go around
i hope the potting with the promix works as expected (lots of great growers use it)
please do not give up and try to have fun with it
we will be watching for your updates
good growing