Low cost mod to HOBs:
I was asked to post pictures of my "low cost" HOB mod, well, not really touching the HOBs at all but basically turn 1 HOB into 2 and more.
First, get the utensil holder from your local dollar store. They look like this, you may find different types but what you want are 1. right size. 2. with holes on the side/back (or you can drill you own). 3. with very good suction cups (the one I have, it's so hard to get it off once it's on).
I put it on top of a AC 20 for size reference.
Then, line the inside with filter floss to block the holes you don't want water to flow through. This way, you can change the direction of the water flow. I find this very helpful. With HOBs like AC, the water tends to go down instead of on the surface and that can blow the plants and shrimp around.
After that, add your favorite filter media. I use Seachem Matrix, it's much cheaper buying in bulk. IIRC, I pay less than $40 for 4 liters. And then, place it in the tank directly under the HOB. And you're done.
The benefits of this mod:
1. Increase the amount of biomedia.
2. Direct the water flow however you like.
3. Create space for moss or other plants. (I don't have it the pic but you can attach moss on the outside of the utensil holders).
Also, on a side note. You can find a lot of goodies at dollar store. I mean, you can get stuff like gush glass plant holder for $40 from LFS or something from dollar stores for < $2 to get something that works the same.
Here, the soap holder -- $1, the clay plant pot base 3 for $1.
The one in the picture isn't planted yet as I was just making it to take a pic. Here is one that has pellia attached.
These soap holders are a cheap way to add real estate in your shrimp tanks, and because it's up in the water, plants grow better because they're closer to the light source. The clear ones look better. You can also attached moss directly on it to create a "garden in the sky".