UV Light, what to expect?

Discussion in 'Newbies to Garden Ponds' started by vestaviascott, Aug 12, 2017.

  1. vestaviascott

    vestaviascott

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    I have just installed a brand new 10 watt "Pondmaster submersible UV clarifier" (Model 02910) inline with my 750 GPH "Atlantic Tidalwave pump" (Model MD750).

    The instructions for the UV light say:

    "For best results, the total amount of water in the pond should pass through the ultraviolet light no less than once every 3 hours".

    I'm a bit confused by this statement. It would appear that the more time the water spends inside the UV filter chamber the better, therefore, I would expect the statement above to read "...no more than once every 3 hours".

    What am I missing?

    My pond is appx 500 gallons, and I've got the pump throttled back a bit at the fountain (to prevent it from overflowing my fountain channels) so I expect I'm getting about 1 to 1.5 complete cycles per hour. or 3-4 every 3 hours.

    I suppose time will tell if I've got it right and the UV helps to clear the water up after a few days. However, I suppose there is a balance between more water changes per hour through the pump filter and less water changes per hour through the UV filter. They appear to be trying to achieve the same result, but need the opposite in terms of water changes per hour.
     
    Last edited: Aug 12, 2017
    vestaviascott, Aug 12, 2017
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  2. vestaviascott

    Meyer Jordan Tadpole

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    That does appear to be a typo in the product instructions, because 'dwell time' is what ultimately affects the effectiveness of a UV.
    With your 500 gallon pond I would recommend that the flow rate through the UV module be no more than 170 gph.
     
    Meyer Jordan, Aug 12, 2017
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  3. vestaviascott

    vestaviascott

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    OK, since my pump is 750GPH, I'll need to install an inline ball valve to get the flow rate that low. What do you expect that to do to oxygen levels?

    I'm about to do my first water chemistry test this am, btw.
     
    vestaviascott, Aug 13, 2017
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  4. vestaviascott

    vestaviascott

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    Here are my test strip results, FWIW...

    [​IMG]

    Chlorine basically zero. Alkalinity somewhere between 40 and 80 and PH on the high side, somewhere between 7-8

    Taken just a few minutes ago. The UV has been running since Friday afternoon (but since the flow rate is 750GPH, I think its likely not having any effect), fish introduced into the pond yesterday around mid day and the visibility of the pond is worsening as of today vs Friday.

    (Newbie comment about adding chlorine to improve water clarity removed to prevent further embarrassment, lol)
     
    Last edited: Aug 13, 2017
    vestaviascott, Aug 13, 2017
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  5. vestaviascott

    Lisak1

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    NO CHLORINE IN THE WATER!! You'll kill every living thing!

    Your pond needs a chance to balance itself - patience is your best friend right now.

    AGAIN - NO CHLORINE!!
     
    Lisak1, Aug 13, 2017
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  6. vestaviascott

    vestaviascott

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    Got it. No Chlorine!!! Thanks :)
     
    vestaviascott, Aug 13, 2017
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  7. vestaviascott

    Lisak1

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    PHEW! You almost gave me a heart attack there @vestaviascott !

    Now for a more calm response - a new pond will go through a period of adjustment. How long that takes depends on many, many factors. But one thing you don't want to do is disturb or disrupt that natural process. Interfering will only prolong the time it takes for your pond to balance. You will think it's never going to happen and then one day - BOOM! Clear water!

    Anytime people say "it's been X number of weeks, months, years and my pond is still green" I will GUARANTEE you they have been adding all kinds of bottled quick fixes. Killing the algae isn't the answer - eliminating the reason it's there in the first place is the long term solution.

    You can encourage the process by A. making sure you have plenty of plants B. making sure you aren't overfeeding your fish C. making sure you have lots of aeration.

    Plants can take a while to get established, so initially they may not be much help, but add them anyway. And remember that the algae or green water that you are observing is also helping - it's not the problem, but rather a symptom and also a helper until your pond gets cycled and your plants get growing. It's eating up the same nutrients that will eventually feed your plants, once things get established.
     
    Lisak1, Aug 13, 2017
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  8. vestaviascott

    vestaviascott

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    Thanks Lisak, so about the UV light and going to the trouble to reduce the water flow of the pump, I'm guessing by your response that you would pull the UV out or unplug it until things stabilize on their own? And if I leave things alone, are we talking days, weeks or months to expect things to stabilize?

    My main concerns at this point are:

    1) I want to insure that my pump flowrate is calibrated properly to insure the fish are getting enough oxygen. Currently, its at 750GPH in a 500 Gallon pond. Since my fountains don't flow directly into the pond or create splash, they drop into a shallow basin. The water eventually makes its way over the side of the basin and into the pond. I'm hoping that the spilling of the water generates sufficient oxygen, but I'm obviously not certain.

    2) I'm losing about an inch of water per day (about 3-4 gallons based on my pond size). I'm not certain if that's expected evap or I have a leak (likely one of my corner folds dipped below my expected waterline).
     
    vestaviascott, Aug 13, 2017
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  9. vestaviascott

    Lisak1

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    I don't use a UV at all so I can't really offer any advice there. Some people use them and swear by them as the only way to get rid of green water. I would offer my own pond as evidence that that isn't true, but to each their own I guess! Perhaps someone will more experience will chime in here with a better answer to that question - it's a good one!

    As for aeration - have you considered adding some air stones to increase the oxygenation? The GPH that you are pumping - I think... someone will correct me if I'm wrong - has very little to do with how much oxygen you are adding to the pond. It's related to how often your water passes through your filtration.

    I answered your "leak" question on the other thread.
     
    Lisak1, Aug 13, 2017
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  10. vestaviascott

    Gemma

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    whew... you had me scared for a minute there:)
     
    Gemma, Aug 13, 2017
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  11. vestaviascott

    Meyer Jordan Tadpole

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    Do you have a Dissolved Oxygen test kit? The only true way to know what your Oxygen levels are at any given time. Relying on fish behavior is risky. By the time they exhibit symptoms of low Oxygen, it is almost too late.
    Generally speaking, something in the overall system of a pond has to be seriously out-of-kilter for Oxygen levels to drop below 3 mg/L (the lethal lower limit for Koi and usually Goldfish).
     
    Meyer Jordan, Aug 13, 2017
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  12. vestaviascott

    Jimmy Gibson

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    The way I use my UV, I only use it when I need it. If I see my water getting cloudy/green I turn it on for about a week or until the water clears. This extends the bulb life and saves a little electricity. I haven't had to turn it on in over a month now, since my plants have kicked in and keeping the Nitrites down
     
    Jimmy Gibson, Aug 13, 2017
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  13. vestaviascott

    vestaviascott

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    My pump is housed in a prefilter basket similar to the one shown below.

    [​IMG]

    There is about 3 inches of fiber like material that completely surrounds the pump with only a hole for the pump cord and pump outlet. The pond water volume passes through this filter appx 1.5 times per hour.

    In terms of oxygenation, here is a look at my waterfall assembly. The water is collected into this shallow basin and flows over the edge into the pond. Because of this, the water surface is extremely still and calm - perhaps too much so.

    [​IMG]
     
    vestaviascott, Aug 13, 2017
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  14. vestaviascott

    Meyer Jordan Tadpole

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    Do you have a healthy green coat of algae forming on the sides and bottom of the pond? If so, you have enough Oxygen as long as you control the fish population. Algae is the prime source of Oxygen in any aquatic environment.
     
    Meyer Jordan, Aug 13, 2017
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  15. vestaviascott

    vestaviascott

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    Sides and bottom are very slippery but not yet green.

    Question: Which is the better bog material, gray drainage gravel or pea gravel?

    I have some standing water at the back of my fountain basin and I want to fill in the base of the basin with smaller rock (the mexican beach pebble are 1-2 inches) in order to fill in the gaps and force more of the standing the water to drain.

    I like the drainage gravel because its gray and blends in well with the mexican beach stones so you can't really tell its there, but I fear that the jagged edges may be potentially harmful to the rubber liner.
     
    Last edited: Aug 13, 2017
    vestaviascott, Aug 13, 2017
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  16. vestaviascott

    Meyer Jordan Tadpole

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    My personal preference is Egg Rock. It allows for better flow because of the larger void spaces.
     
    Meyer Jordan, Aug 13, 2017
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  17. vestaviascott

    vestaviascott

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    Thanks Meyer, what I'm trying to do is fill the voids to force more of the water out over the spillway into the pond. I'm leery of the stagnant/standing water accumulating in the void areas between the rocks on the backside of my fountain basin.

    For that reason, I'm trying to decide between the smaller stones (brown pea gravel vs gray crushed drainage rock).

    I've seen a video where Eric Triplett used pea gravel for a bog project so I know that will work fine, I'm just trying to determine if the drainage gravel would work equally well (since I like the color of it for my design) and if I should be overly concerned with potential liner damage from the jagged edges vs the smooth edges of the brown pea gravel.
     
    vestaviascott, Aug 13, 2017
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  18. vestaviascott

    Meyer Jordan Tadpole

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    No matter what is used in the 'bog' the water will exit over the spillway when the 'bog' is full.
    The smaller the void space, the quicker the 'bog' will clog. All you are really seeking is some form of substrate that will provide anchorage for the plant roots in order to support the top growth. You are more likely to have stagnant/standing water occurring with smaller void spaces as these will impede water flow/circulation especially when you factor in the plant roots.

    But in answer to your question, choice of substrate surface texture would be a decision based on cost and aesthetics.
     
    Meyer Jordan, Aug 13, 2017
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  19. vestaviascott

    vestaviascott

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    I suppose I just need to fix the slope so that the water doesn't settle in the basin. I need all of the water diverted to the pond, not stagnant in the bog. As it is, I apparently have a low spot at the back corner of my fountain basin. Ideally, the basin should slope towards the pond.
     
    vestaviascott, Aug 13, 2017
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  20. vestaviascott

    Meyer Jordan Tadpole

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    Are you utilizing a diffuser pipe on the bottom of the 'bog' for the inflow? And do you have it positioned in the center of the 'bog'?
     
    Meyer Jordan, Aug 13, 2017
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