I have placed over the head water tanks on top of an elevated concrete structure with grading.

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But I can see lots of algae growth beneath it , I honestly didn't expect this because it's open terrace and have white tiles so lots of sun light and heat is reflected hence the water would evaporate along with that.

I can see 100 percent there's no water leak from the water tank also.

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Since the tank has been fitted with the pipes I'm afraid to move that and clean beneath the tank but it seems like this is the only way to clean now.

How do I prevent this from happening again

  • 1
    Probably rain collecting on the tiles. Getting under the tanks either by capillary action or simply flowing underneath, since the tiles appear 3-dimensional. The water that gets underneath doesn't evaporate as quickly because no sun or air movement, so you get algae/mold growth.
    – Huesmann
    Commented Oct 5, 2023 at 13:49
  • @Huesmann - yes you are right. makes sensse
    – Amogam
    Commented Oct 5, 2023 at 21:47

1 Answer 1


In very moist environments in the US, many people get moss growing on their roofs. Often, zinc strips are placed near the peak of the roof, allowing very small amounts of zinc to wash off with each rain fall and wash down the roof before hitting the gutters. This gentle washing of zinc kills the moss.

I would imagine that zinc strips placed under your water tanks would also kill the algae that grows there. As water collects (from whatever source - leaks from the tanks, condensation, whatever), it will slowly dissolve the zinc and allow it to spread.

You could start with one strip to ensure that it works, then add more as necessary to ensure that you're getting enough spread to kill the growth wherever it's happening.

  • 1
    Zinc or zink®?
    – HABO
    Commented Oct 5, 2023 at 14:57
  • That's great. I googled about this a bit and I saw how they place it in the roof. but how do I place it for my tank .. like should I cut a pieces of zinc strip and cover the edges of the tank ? Some idea would be great
    – Amogam
    Commented Oct 5, 2023 at 21:47
  • 2
    Grab a bucket of water, pour it near the tank, and see which direction the water flows. Put the strips on where it flows from. If it just sits there and doesn't really flow, then unfortunately you may just have to cut it up and put it all around the tank.
    – Nelson
    Commented Oct 6, 2023 at 1:18
  • Yup, what @Nelson said.
    – FreeMan
    Commented Oct 6, 2023 at 11:42
  • Simply winding a zinc wire around the base—where the algae is—may suffice.
    – Huesmann
    Commented Oct 6, 2023 at 12:30

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