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  1. #1
    Extreme Koi Member Rank = Hassai NickK-UK's Avatar
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    Recycling RO - using RO to clean pond water.

    Interesting take on RO.. and one that had occurred to me (although I'm in no position to try it):



    So rather than trickle water, RO is used to filter return water on a 1 hour on, two hours off basis. They are using a 20 micron and carbon cartridge filter.


    1700 litres on 50 watts
    Planned 11,777 litres on 58 watts. 1300l anoxic, 4" airlifts, Solum 16, bio.

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    Senior Member Rank = Hassai Sim's Avatar
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    Yes I was thinking of doing this but wasn’t sure how long the membrane would last with bio film etc, also thought it may be better to have 20 and 5 micron and nothing bother with the carbon as wasn’t really sure what it would do.

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  5. #3
    Extreme Koi Member Rank = Hassai NickK-UK's Avatar
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    Quote Originally Posted by Sim View Post
    Yes I was thinking of doing this but wasn’t sure how long the membrane would last with bio film etc, also thought it may be better to have 20 and 5 micron and nothing bother with the carbon as wasn’t really sure what it would do.
    Was thinking of bio build up on the membrane too. I suppose if you do that then using an ozone supply ahead of the membrane would reduce/prevent the build up.

    Also it seems that most KOI RO systems are running on timers for the auto flush. As the valves are 12V or 24V I'd be tempted to make a Arduino based system that monitors pressures rather than rely on a timer. That way you can limit the pressure levels to the optimum.
    1700 litres on 50 watts
    Planned 11,777 litres on 58 watts. 1300l anoxic, 4" airlifts, Solum 16, bio.

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  7. #4
    Senior Member Rank = Hassai Sim's Avatar
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    Yes they flush them often my ro at the moment hasn’t got an auto flush, They seem to flush out a lot more with recycling.
    i hadn’t thought about ozone, there’s a unit I saw that looked like a UV would be easy to connect before, would ozone affect a membrane though?
    also two prefilters say even 10 and 5 micron changed say every 6week do you think would reduce the bio build up.
    they are cheap so if it protected the membrane would be worth it.
    there are a few that clean membranes but again this is another cost and time consuming.

  8. #5
    Extreme Koi Member Rank = Hassai NickK-UK's Avatar
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    Quote Originally Posted by Sim View Post
    Yes they flush them often my ro at the moment hasn’t got an auto flush, They seem to flush out a lot more with recycling.
    i hadn’t thought about ozone, there’s a unit I saw that looked like a UV would be easy to connect before, would ozone affect a membrane though?
    also two prefilters say even 10 and 5 micron changed say every 6week do you think would reduce the bio build up.
    they are cheap so if it protected the membrane would be worth it.
    there are a few that clean membranes but again this is another cost and time consuming.
    There's a couple of ways to produce ozone - UV at 185nm is the normal way. The UV at that specific wavelength produces ozone - it's then added into air being bubbled (the bubbler also recycles the air/ozone mix at the top) that sterilises vs UV at 236ish that kills the cells via direct irradiation and damaging the cells.

    O2 is an oxidiser so it depends on the membrane I suppose. This may be of interest: https://www.tandfonline.com/doi/abs/...12.2011.607385 which shows that it reduces fouling of the membrane.
    However (from 1983) "Ozone was the most agressive chemical disinfectant tested. All membranes used in this were damaged..." (page 13): http://www.mrzgroup.umd.edu/pdfs/1983_desalination.pdf

    So it looks like O3 ahead of RO - works in that it prevents fouling but the O3 itself oxidises the membrane. However O3 is very short lived, so it's possible to treat the water such that O3 isn't passed into the membrane (it quickly returns to O2). So it's possible .. but you'd want to have a O3 monitor in the water before the membrane and automatically vary the rate of O3 production.
    1700 litres on 50 watts
    Planned 11,777 litres on 58 watts. 1300l anoxic, 4" airlifts, Solum 16, bio.

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  10. #6
    Senior Member Rank = Hassai Sim's Avatar
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    Thanks for the info, starting to get complicated will have to look into a lot more.
    I had want to run the ro off the main pond pump which would then go through the two pre filter and onto the ro.
    if you put the 03 In front of the pre filters would they get rid of the 03 do you think?
    most ozone I have seen seem to go through protein skimmers and then returned to the pond

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  12. #7
    Extreme Koi Member Rank = Hassai NickK-UK's Avatar
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    Quote Originally Posted by Sim View Post
    Thanks for the info, starting to get complicated will have to look into a lot more.
    I had want to run the ro off the main pond pump which would then go through the two pre filter and onto the ro.
    if you put the 03 In front of the pre filters would they get rid of the 03 do you think?
    most ozone I have seen seem to go through protein skimmers and then returned to the pond
    Interesting piece on the halflife in air and water (pH 7): https://www.lenntech.com/library/ozo...omposition.htm this would also be pure water I assume. So in water every 20 minutes there's 1/2 as much O3. However read down a little and section 3 shows with real word dissolved solids and effect of carbonate. Also not shown here is that pumping energy back into the ozone again quickly destroys it:

    O3 is nasty stuff. It is possible to biocide the entire pond including the fish. So it really needs automatic monitoring and adjustment. Ideally you want to treat the water going through but not have O3 in the pond.

    Here's an interesting point - using 254nm UV destroys Ozone: https://www.aquafineuv.com/Ozone-Destruction - by using an amalgam UV light after it's likely to convert the O2 back to O2.

    pond -> filtration -> ozone -> sump (to allow dwell time with O3 - this could be a protein skimmer for example) -> amalgam UVC - then a % of pond return --> reverse osmosis -> pond

    Although you don't need the amalgam UVC for sterilising with ozone systems (the O3 does that) you use the amalgam to safely counter the O3 before the very sterile water is returned to the pond (or via RO).

    If you do take the protein skimmer route - it's safer (given the foam is likely to have O3 and so too will the air exiting from it) that the air is recycled through the air pump inlet. It's sterile but the O3 may attack the diaphragm however it means you recycle the escaping O3 and you don't end up with a filter house of O3 which is extremely bad for your health.
    1700 litres on 50 watts
    Planned 11,777 litres on 58 watts. 1300l anoxic, 4" airlifts, Solum 16, bio.

 

 

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