Hopefully someone else who has actually had problems with algae will come along. I have only had/have string algae that I have heard will compete with single cell algae. Perhaps that is why I have never had a pea soup problem.

I suspect that the in line UV lights that pump the algae water thru the fixture actually work for a year or so. We just had someone whose pea soup began to go away after replacing a several year old UV lamp. However, they also added a good many more in pond plants that provide both shading and nutrient use. That could have contributed to the improvement. We have generally heard that pea soup will clear up in several weeks. Perhaps you have just not waited long enough. Of course I also suspect that what ever chemicals you bought were mainly useful to the provider's bottom line.

So: it might be useful to add a UV device and almost everyone agrees that more plants are helpful or necessary.

What are your water parameters right now? It usually takes more than 8 weeks for a pond to cycle and it sounds you put fish in quickly. My guess is that your filter isn't close to be cycled yet and you are having an ammonia overload...algae feed on ammonia. I would leave the algae b/c right now it is helping to protect your fish by feeding on the ammonia. I would definitely get an ammonia binder in the water every 24-48 hrs asap until your filter tests as cycled (ie Safe, Prime, etc). You will also need it to protect your fish from nitrite poisoning when it spikes after the ammonia drops. When you use an ammonia binder, you will get a false-positive testing for ammonia so you will need an Ammonia-alert disk like this to put in the water to show the harmful ammonia vs total ammonia (https://www.amazon.com/Seachem-67100100-Ammonia-Alert/dp/B000255R5G/ref=sr_1_1?ie=UTF8&qid=1465857042&sr=8-1&keywords=seachem+ammonia+alert).

Wanted to add...most important parameters to keep track of are:

Ammonia

Nitrite

KH (indicates stability of pH)

PH 8.3, ammonia 0.25, Nitrite0, nitrate, 0

PH has not changed in 2 1/2 weeks since I started testing. Just added cotton batting and cleaning out tons of junk 3 x a day...will continue to change pads.

Will add more plants since the pond is not shaded morning to 130 pm.

Only added microbe lift and Spring startup bacteria

Yes, you are cycling. You definitely need an ammonia binder until it fully cycles