I've noticed that even when I reduce the flow, the substrate in the foreground area gets pushed back. The sand is being pushed onto a few delicate plants, and also shrinking the sand cap by quite a bit. Is there any way to reduce the flow even more?
Am on my phone at the moment (so I can't do extensive searching to find links for you) but if you search the forum for "filter baffle", you should find a few examples. People have used everything from shower caddies to water bottles to attach beneath the outflow to help calm the water. Seems to work really well.
My favorite baffle trick is just to add a piece of sponge on the outflow.
I used an idea I found here. Take plastic mesh (I got mine from michaels) and cut a strip the width of the filter. Stick it into the filter a bit between the housing and the media. Then I used a suction cup to stick the bottom of it to the glass under the filter. The water follows the mesh down, and you can even attach mosses to it! Dunno if it'll work for you since your filter is much higher power. Otherwise a normal baffle will work
On my AC300 filters (old name for AC70) I drilled 2 1/8" holes a little was up from the output lip. Takes a good eye to get it right. I then took a large vinyl tube and cut it to fit the width of my out put. I cut notches in one edge like a door hing and drilled small dia. holes. Fairly difficult I found it, lol. I then slid a plastic dowel thru it. It definitely achieved what I wanted. I needed it to not throw the water out as far on top my glass tops. It diffused itself downwards and towards the back glass decently. Alot depends on the dia tube you use and where you cut it in half.
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