Question
QUESTION: hi, we have bio filter and pump with waterfall. It has worked great for past 3 years giving crystal clear water. we fitted a new impeller to the pump in the last few days which looks all to be working mechanically really good. I have noticed the the water becoming less clear. Some of the fish were congregating in the corner where it was a warmer part, never noticed them to be doing that before. Some of them seem a little listless and one of them looked like it was on its last legs though on appearance its skin etc is great. We cleaned the filter yesterday i removed some debris. Did a ph test which is acceptable 8.5 and the nitrate is ideal so its not that. Usually when anything is disturbed within a short while its crystal clear again but this morning its worse than ever and i cant see the bottom of the pond.  Theres tiny particles all through the water.  The uv light is still working.  Whats happened please help. My husband says impeller could only go one way, yes ive asked him this i know its a silly question. He rinsed all the foam inside the filter the same as he always does with the pond water in a bucket to maintain the balance in the bio filter then the water is thrown away onto my garden plants (been told theres nothing finer for your plants) Please help asap. many thanks

ANSWER: Hey Tina, I have no idea but I suspect it would be the last thing I worked on. I always go to the seen of the crime. If it was clear before and you changed the impeller then I would think that is what it is. Maybe the pump is wore out or the impeller is not the right one. It has to take in a lot of water to keep your pond clean. Green cloudy water won't kill your fish. My water is green and I have had my fish for years. I can't have clear water the coons can see the fish and eat them. I live in the middle of the woods. Lots of critters looking for something to eat. Hope this helps, Thanks Eric

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QUESTION: Well the impeller is exactly the same as the one we removed. We have also put in a new uv light.  I have used green away as the stuff also coating the plants is green so i presume thats what is floating in the water. Its not quite as cloudy but still not clear, stuff  is still floating.  Those two fish have died though i could not see anything physically wrong with them.  I am used to the water always been crystal clear. Can you suggest anything else? many thanks tina

ANSWER: Hey Tina, if there is green stuff floating in the pond it is algae. The bio filter should be taking that stuff out of the water. Have you cleaned out the waste in the bottom of the pond? Try making a partial water change and see if that helps. If all the media is changed in the filter and water is going through it the filter should be full of the stuff. Make sure the pump is still pumping the same volume of water it was. If it is slower then the filter won't be able to keep up. Its possible the pump is just wore out. Those pumps have a shaft that is ceramic coated, and when the coating wears off they are no good.Thanks Eric

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QUESTION: hi Eric, sorry  to peck at your head. As far as i can tell the pump is pumping the same amount of water as it always has.  There is no change in the flow of water down the waterfall. The sponges in the filter do get dirty and get cleaned with the pool water in a bucket as the filter is a bio one.  Could it be just the fact that its spring and now the pond has been established for three years its just a normal occurance and needs a good clean out. I have a pond vac that i have used once it just is that messy and i have nowhere to put the fish while i am doing this. I have always used a net and dragged from the bottom on a regular basis but do you reckon thats not enough? Iknow this all seems trivial but i want my crystal clear water back. thanks again, tina

Answer
Hey Tina no problem I am just trying to  eliminate some things so we can figure out what is going on. I have a 1700 gallon pond that I clean out every year. The stuff on the bottom (waste) is toxic to fish and will cause the water not to be clear. I also have 2 salt water aquariums so I am very aware of filters and when they need changed. It has to be something. If we eliminate everything whatever is left however improbable has to be it. Thanks Eric