Brownish clouding in pond - water change didn't help-killed fish
I have an approximately 5 x 3 x 3 foot pond with some fish and lilly and anacharis/hornwort, etc, and waterfall flow coming from a filtered 250 gph pump.
I have had the pond for 5 years or so now and have never had this issue. This spring, I decided to drain the pond and give it a good cleaning since I never really had drained it in the past. I took out 90% of the water, which was probably a mistake. I filled it with the garden hose (well water) and so as to not shock the fish, tossed in a few pots of hot water as it filled to mellow the shocking coldness. I added some of the water conditioner/fish slime protector stuff, some then some algae killer in defense of algae growth, and some of the dirt coagulator stuff. After filling, the water was briefly clear, but then got brownishly cloudy. Unfortunately, my pond pump shorted out and failed for two days without me noticing. As you probably know, no water movement with the algae killer and coagulator stuff = not good. Even though I replaced the pump and got the water moving within 48 hours, I had 7 fish die on me over the following week. They were all the smallest ones...so I'm guessing that just being smaller made them more succeptable to not surviving the harsh conditions.
Now the fish that are living seem to be fine, but, the pond is STILL quite cloudy and dirty looking. Not algae from what I can tell, but permanently suspended really tiny brown dirt stuff. I clean the filter a lot but that doesn't seem to help. I can only see down about 3-5" in the water, as it is now. I'm almost scared to add some more coagulator, since the fish may still be in shock from the first round of torture.
I thought I read somewhere about wrapping a type of cheesecloth around the waterall hose and having the water go through this "microfilter" and catch the particles that are apparently just suspended or passing through the filter. Not sure what else to do!
No koi, only goldfish, so it's not that I have fish uprooting plants and stirring up dirt. I've had the same lilly pot for years and haven't had this issue (still plenty of gravel on top of the dirt) and the dirt in my top level plant pot is black organic potting soil, way darker than the lighter borwn cloudyness of the pond. Oh, also, no real rain has occured to blame runoff, and I've never had a runoff issue in the past.