Tips on converting a sand filter to a pond filter

A pool is close enough to a pond right? So if I have a sand filter keeping my pool crystal clear, I can just as easily hook it up to my pond right? Let me ask you something, you wouldn’t hook a bio filter to your pool and expect it to do the job, would you? While a sand filter works to keep your pool clean, I really do not recommend trying to filter your fish pond with sand.

When it comes to pressurized pond filters, there are a few reasons why you don’t want to use sand.

  1. It will require a much larger pump to operate which can result in higher energy usage.
  2. Because sand is so fine, the waste produced by fish will build up on the surface and clog the filter from working.
  3. You need to backwash the sand filter daily to prevent waste from clogging it up.
  4. If the sand does get clogged, it won’t be able to backwash properly and will have to be cleaned by hand.
  5. Sand makes a poor living space for beneficial bacteria and therefore has no bio filter properties.

So now that you know why sand makes a bad filtration system, there are alternative media you can still use in your pressure filter. Bead media and micro bio filter media require less energy to operate, are easier to maintain, and have more biological surface area than sand. Just make sure you install a screen to cover the exit so the lightweight beads don’t get flushed out when backwashing. I recommend something that is just big enough to let out dirt and not the beads.

When you convert a pressurized sand filter to a bio unit, you only want to fill the tank up half way with biological filter media (I recommend using Easypro Ultimate Floating Media). Next, you want to watch your flow rate through the filter, if the water goes through the filter to fast, the filter will be ineffective biologically. I don’t advise hooking a pump up directly to the filter. Instead, you want to use a flow regulator so that you can control the pressure more. The water should go through slower when running in filter mode and the flow should be increased when backwashing. For flow rates, I suggest emailing us at and asking for some guidance as far as what you will need to push. Before you call in, please have the following information available: tank diameter and height.

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