How long do filters last?

[pkv]

I bought a house with a 5000 gallon pond with 20-30 koi. Have struggled over the past couple years to get the water clear. Have a waterfall and a pump with a fairly high gpm flow. The bio filter looks very old to me - is 6' tall and about 2' in diameter. There are 3 40-watt uv lights inline after the filter. Part of the water goes through the filter and the 3 uv lights while part goes directly to the waterfall.

I have replaced all 3 uv lights and backflush the filter weekly, but still have green water with lots of visible green particles in it. Key question I have it whether the filter is just too old and needs to be replaced... Any thoughts?

Thanks from a newbie...
Peter

 

[Craig58]

The filters themselves should last forever. What can have problems is the media in the filter. And that depends on the media. Smaller media like what is in bead filters or some small plastic types of media can get packed and filled with debris that causing channeling in the media. Think of how water in mud causes little culverts and erosions in the mud. The same can happen in smaller media such that the water just runs through. That media can usually be replaced or sometimes cleaned. Other media like foam panels can get clogged and also might need to be replaced. Larger media like hair curlers, bio-balls can sometime be cleaned. Lava rocks and similar media can sometimes be cleaned but also usually will need to eventually be replaced. Otherwise, no, with proper cleaning, regular maintenance and occasionally replacing media, a filter should last forever. Now pumps are another story!!!

Craig

 

[pkv]

Thanks Craig. I bet my media is very old - at least 5 years old and maybe 10+ years old - and may need to be replaced. Is this something I might be able to do myself or should i hire a professional?

so far my pump is running well!

 

[Waterbug]

A bio filter would not affect green water. Actually the algae causing the green water would normally consume ammonia directly, faster than the bio filter.

That you have green water means the UV filters aren't working. Consider posting a picture of them. They are sometimes installed upside down, air gets trapped inside and they don't work very well.

The other, more common issue, is too much water moving thru them. Manufacturer specs are always for the max flow. Heavy algae doesn't allow as much UV to penetrate so flow has to be reduced. I assume the units are plumbed in parallel and not in a series. For multiple units you need a valve before each unit to control the amount of water going thru each unit. You also need the outflow of each unit, to be open, like where it dumps into the pond, so you can see how much flow is actually going thru. If the outflow of each unit is plumbed back into a single pipe you have no way to know if 40% of flow is going thru one unit and 30% thru the other two, or whatever.

The idea is you dial down the flow and wait 5-7 days to see if green is reduced. If not, you dial down some more. If that doesn't fix it there's another problem.

As long as the bulbs have less than a year's use and the units turn on, they don't need to be replaced.

 

[Dave 54]

[sup]Just so you know all UV-C Bulbs have a working life of one year before they loose their effectiveness and thus need replacing unless they are the new generation UV-C that have duo bulbs and need replacing every two years.[/sup]

[sup]rgrds[/sup]

[sup]Dave [/sup][sup] [/sup]

 

[Craig58]

Thanks Craig. I bet my media is very old - at least 5 years old and maybe 10+ years old - and may need to be replaced. Is this something I might be able to do myself or should i hire a professional?

so far my pump is running well!

Depends on the filter type but replacing media is usually no big deal. Most everyone does this themselves I would think.

But as I said in your other posting and WB indicated here, the filter isn't what is causing your green water. And if your UV's are working right, it should not be green.

Green water is usually caused by high nutrients in the water. The nutrients are usually taken up by other plants in the pond. UV's kill the floating algae directly and so, if using properly sized and installed UV's you shouldn't get green water to start with. As more plants grow and more complex algae grows on the walls and objects in the pond, they take up and compete for nutrients and reduce the algae that causes green water. To solve green water you usually increase the plants in the pond to reduce nutrients, cut back on feeding and fish to reduce the nutrients, or increase UV capability to kill the floating algae directly. A combination of all three can sometimes be necessary and maybe required if conditions get really bad. Sometimes a 50% water change can help too when you undertake the above mentioned steps.

Is there any chance as new home owner/ponder you recently cleaned the pond and scrubbed off the algae on the sides and on the rocks, etc.. in the pond? This could have caused an increase in the nutrients in the water since the wall algae is no longer there to utilize them. It could have caused a green algae bloom.

Craig

 

[sissy]

Why do you say you backflushed the filter :question: Is it a sealed unit or open .I have not had to clean my filters all year so far .After I added plants to the filter all I clean is the top fine filter basket material .