Read my first review of the 501 Zoo Med Turtle filter here . In that review, I went over my experience of using it with two hatchling red ear slider turtles in a 5.5 gallon tank with 3-4 gallons of water.

This review is an update. I’ve been using it to filter the same 5.5 gallon aquarium filled to the max with water, but set-up this time as a planted fish & shrimp tank instead of a pet turtle tank.

Maintenance. In the year that I’ve been using the 501 turtle filter for the fish tank setup, I’ve only had to open it up for cleaning three times. The first time was because I had to change the filter media inside. At that time I was only using the mechanical (sponge) and biological (ceramic rings) as my filter media. Because I was going to add some new driftwood into the tank, I needed to open it up to add some chemical filtration (charcoal) to filter out the tannins that would leak from the driftwood. The filter didn’t need maintenance cleaning at the time, but since I had to open it up, I cleaned it anyway.

The second and third time I cleaned the turtle filter was after I added laterite to the aquarium gravel. Laterite is a clay-like substrate that is supposed to be good for planted tanks. Although I’ve read that natural, lo-tech setups like I have don’t need laterite, I wanted to try using some anyway. When I first added the laterite, the water got so intensely cloudy. The cloudiness settled down and was picked up by the filter in the next two or three days. The laterite powder in the water column clogged up the filter and I had to open it up to clean out the laterite. About six weeks later, had to open it up again to clean out more laterite, as I had rearranged the tank a few more times, sending more laterite about to cloud up the water.

Priming the 501 Zoo Med turtle filter is simple. Just fill it up with water, plug it in, and it’s running. Can’t get simpler or easier than that.

Noise. A very quiet filter. It only makes noise after you first prime it, when it’s getting rid of excess air in the filter. Once that’s all gone, it’s as quiet as can be.

Options. As with all canister filters, it comes with the usual strainer input and a spraybar output option. As with all canister filters, you don’t have to use the included output / input parts and you are free to use what you want and modify as necessary.

For the input strainer, I don’t use the one the filter comes with. I really want to minimize the chances of getting shrimp and fish fry sucked into the filter and the included strainer’s holes are too big. I use a double layer of fiberglass mesh wrapped around the tip of the input tube. I haven’t seen any fry in the filter.

I don’t use the spraybar as well. I actually just have the water shooting straight into the tank. With my pet turtles, I never filled the aquarium full of water and I used the spraybar. It was easy to visually and audibly find out if the filter was running and whether it was starting to get clogged up. Now, with the fish tank full, I have to rely on some bacopa under where the water is poured into the tank. If the bacopa leaves are swaying a lot due to the water current, I know the filter is running. If it doesn’t move, then the filter is clogged and should be cleaned.

Filter media options. Same thoughts as in my other review: "Comes with all the media you need and is ready to use right out of the box. It comes with a sponge (mechanical media), a carbon bag (chemical media), and ceramic rings (biological media). Carbon isn’t really needed in a turtle tank, but if you really wanted to continue using it, it would be cheaper to buy your own carbon than to keep buying the Zoo Med branded carbon packs. I prefer to ditch the carbon and just use more biological and mechanical filter media instead."

Strength. The filter is no Hoover but it does what it has to. A filter shouldn’t be so strong as to be able to pick up all dirt from all over the aquarium. That would result in an aquarium with way too much water movement, which isn’t good for most aquarium animals and plants. The filter is able to pick up "floaties" near the input tubes. I’m happy with the strength of the turtle filter. I could see some people wanting a filter with more GPH (gallons per hour) as my opinion is that it would be underpowerd for a 10 gallon or larger tank. But I’m happy with it.

Overall. The 501 Turtle filter is an excellent fish tank filter. Make that "an excellent 5 gallon fish tank filter", since I haven’t used it in any other sized aquariums. I had been using the turtle filter for over two years when I first wrote this and have continued using it and have had no problems thus far.


  1. Can you run the zoo med 501 below the tank ?
    ie Have a 10 g tank on a table & wish to setup ZM 501 below the table, out of view.

  2. I haven’t actually tried that. I read a review before that said it wasn’t powerful enough to do it though.

    How about hiding it from view with a tank background?

  3. This filter killed my turtle. I woke up to find her lifeless body stuck to the filter. I will never use this filter again and hope to save someone else from this tragic accident.

  4. ouch, I’m very sorry for your loss.

    I have read of other turtles getting stuck in their filter’s intake tubes and drowning as a result. This can happen with any filter, so it’s important to take precautions that they don’t get stuck in the first place. Was the filter strainer in place when this happened? How big was your turtle?

    I hope you are feeling better, condolences…

    1. Thank you. I really appreciate it. Yes the strainer was in place. My turtle squirt was about a year old and her shell was a little over 4 inches. Her foot somehow got caught and she drowned.

  5. Wow! I’m surprised by that..I was expecting your pet turtle to be a hatchling.

    I guess you can’t really be too careful – especially since the 501 filter isn’t a particularly strong filter (most regular canister filters are bigger and stronger).

    Once again, sorry for your loss…

  6. do anyone know how long it takes to prime it. I bought one and i plugged it in. so far it only made noise and it’s not sucking any water in.

  7. it’s easy to prime – simply fill it up completely with water. Then, make sure the input and output tubes are in your aqauarium’s water. It’s primed. Plug it in and you’re all set to go!!

  8. Re turtle stuck to intake – I have raised turtles (and rescued many) when young (outdoor kiddie pond, rocks, plants, half sun half shade) and know well the sudden loss – one had a rock tumble on him – and he drowned. After that I used bricks to make sure there were no more such accidents.

    That said – once just prior to leaving on vacation – I went to feed a great fish I had (name escapes me now). A fast swimmer, strong always poking his head here there. I just saw him, came back from fridge (frozen foods) and was thawing the pinch in my fingers to hand feed him… Missing in action.

    To make a long tragic story short – I looked for hours everywhere – my friend waiting patiently. (we had rented a car)…. Finally I noted the filter intake had come off and to take a break from looking all over to clean the filter.(moving furniture so on – somehow even with a lid I thought he had jumped as a powerful fish in carp family).

    I noticed it seemed clogged and used hot water to flush it….. still wouldn’t flush so gave it a hard konk on edge of tub and out HE came – dead of course from the hot water! I cried all during that vacation but his death was not in vain.

    I have no idea how the intake came off but what shocked me is that the inflow to me “was not that strong”…. Then I realized he must have been poking about (often straight up at wood and plants) and just gotten sucked up in what to him was a vornadoe!

    I realized that to him it was a huge flow… they are so small and we just can’t imagine the equivalent force.

    Now I put on filter sponges on all intake tubing – just in case.

    You could easily do that for the turtles as well as keeping the intake in a cage (get some of that lighting grid and make a little partition – many people who build rock formations use it under the rocks) or other creative ideas to reduce the inflow around that area…

    Sorry for him drowning – not easy to come home to I know – still haunts me decades later!

    1. sorry for your loss and thank you for sharing!

      agreed, it is always better to protect your pets. sponge filters/strainers/rocks – whatever works!

  9. Another thing you can do to avert disaster is to remove the input tube from the fishes area. The way I do this is I use an undergravel filter in my 10 gallon tank, raise one of the undergravel tubes above the water level, put the canister input tube inside the undergravel tube, and voila. Make sure the undergravel tube is and always will be above the water line. This setup works really well for me and keeps the area under the gravel nice and tidy.
    Good luck!

  10. The best way to avoid your filter becoming a fish vaccum is to create an overflow box around the intake.

    The box should be as tall as you want the water level overflow to be with “fingers” about 1/8″ apart cut into the top so that the water can just flow over the edge.

    Some also put some kind of screen media/material in front of/over the fingers to prevent smaller animals from flowing through the gaps and into the box.

    Simply adjust the outflow of your filter system to keep enough water in the outflow box to keep the intake underwater.

  11. Can you adjust the flow from the output? I want to use a small external filter to create water circulation for my snake’s water dish (rigged with safety in mind of course) and this is the smallest one I can find, but I don’t want the water roiling around esp. since there won’t be as much water as in a 10 gallon. Someone said that it’s not powerful enough to work when the canister is placed below the tank- would it stop working completely or would that work to decrease the flow without harming the filter?

    1. there is no flow adjustment.

      It isn’t strong enough to run underneath the tank.

      Personally, I think the 501 is overkill for a water dish. Why not take one of these small internal filters, remove the bottom filter part and let it sit in the dish? Just an idea

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