OK, now we have something to work with, BTW, great looking pond! The landscaping is really beautiful. I can see the foam, Not that bad, A skimmer would GREATLY help in making that far less noticeable and would add oxygen as it removes the surface film and allows for better oxygen and Co2 exchange. Now here is the million dollar question, Are there rocks in the bottom of the pond? My bet, there is, That just looks like a typical rock bottom setup, and although very pretty IF it could be maintained, It's a difficult job task to do and many people will tell you this type of set up is one of the hardest to keep, Build up of leaves, waste, and such gets trapped in the rocks, this start to breakdown and can cause many unseen issues.
There are two types of organisms and tiny single-celled bacteria called aerobic and anaerobic bacteria. Aerobics are able to use oxygen, whereas anaerobic bacteria can sustain itself without the presence of oxygen. Aerobic bacteria can detoxify oxygen, whereas anaerobic bacteria cannot sufficiently break down food molecules as
much as aerobic bacteria.
Aerobic bacteria gets energy from food when compared to anaerobic, that can survive in places where there is less oxygen, such as in Rocks or in areas of little or no water movement. Some anaerobic bacteria also causes diseases in those areas of the body where there is less oxygen supplied. Aerobic bacteria cannot grow without an ample supply of oxygen involved in a chemical reaction, whereas the anaerobic term does not imply this.
Here is my suggestions but please before doing any thing make sure you feel comfortable and are ready to take on each step as you feel best fit.
water changes- this will help reduce anything bad that test kits Can't read.
Add filtration, Your filter is the heart of the pond, just as we can't live a normal life without a heart, but can survive if there is ample blood flow and oxygen in our system and can live off of a life support system. A pond works in a similar manner. A pond can support life without filtration, But at some point with livestock and feeding there becomes a point that the pond can't handle the load any longer.
Remove the rocks on the bottom of the pond/If they are in there. net and remove as much build up on the bottom as possible.
Add plants, plants do many functions, but here are the ones that they do that would help you. One they provide shade, If the pond was covered with 50% -75% coverage from lilies and other plants the water would probably stay clear as they would use up the nutrients that the green water is now thriving on, the shade also reduces the amount of sunlight that reaches the pond discouraging algae growth and at the same time helping maintain more stable water temps. Plants also provide food for fish, help reduce waste, add area for bacteria to grow when the roots are exposed to the water column, ( Marginal's such as Taro, pickerel rush, Iris, cat tails, Papyrus, Thalia, etc can be grown directly in the rocks along the edge and do not need pots). Plants also provide protection for fry and provide protection for adults from predators.