Soft Water low pH

[caudelfin]

I have a very small pond, 300 gallons when brim full. It is loaded with way too many gold fish, at least 25 -- 2 or 3 right at 12 inches and the others in various sizes from 10 inches to babies. A couple or fancy goldfish and they have been in the pond since 1998 and stay out all winter. When it ices over I melt a hole in the ice with a pan full of boiling water so there can be a gas exchange. Sometimes I have to do this 3 times per day in Jan. The pond depth is 24 inches.

Now the weather is warming, the pond temp will reach 90 deg F or a few degrees higher in the summer, the hardness is d 1.5 and the pH is right at 6.7 and I am thankful for this as all the ammonia or most of it becomes ammonium and they can live with that. And I let nature take care of the population, which remains pretty much between 20 and 30 fish. Never ever see any bodies floating.

I have a 15 watt [acronym:4c32a10094="Ultra Violet"]UV[/acronym:4c32a10094] and two in the pond filters, one out of the pond filter and that one has a bio converter which is now starting to operate some. It has been too cold before. I presume that the in pond filters contribute to the bioconversion. The water is clear and I can see the bottom, of course it is necessary to clean filters weekly (using in the pond water of course) with the fishload. The [acronym:4c32a10094="Ultra Violet"]UV[/acronym:4c32a10094] helps with the algae and diseases. Perhaps I should leave well enough alone ( Don't Fix It If It Aint Broke) but I would like to raise the hardness to at least D 4 and the [acronym:4c32a10094="power head or Measure of the concentration of hydrogen ions, depending on context"]ph[/acronym:4c32a10094] to around 6.8. What would you advise doing differently, if anything.
caudelfin