Should I trust my HOB?

[Demobanana]

So I have a new planted 20 g I’m setting up, and trying to move everything from my pretty much failed 10 g. The pictures will explain everything. The 1st one is my 20 g, which I’m floating stems until roots come in and I can plant (I have a dirted substrate). All clean, starting to grow a little algae, but nice and green. I got them less than a week ago so I would expect it. The 2nd one is my grimey old filter (a Tetra Power Filter 40 if it matters) , which isn’t old at all but I forget to squeeze the sponges out every once in a while. Pretty much filled with sponge. 3rd one is the 10 g tank the HOB is running on, covered in algae and I’m hoping the new one will run a bit better. Still pretty damn dirty. I do water change once a week but it looks grimey as well. I don’t have a lid because….I’m using mine for the 20g currently. So I put the HOB on the 20g, I have a sponge filter in there and wanting to switch it out with the HOB thinking the HOB has more beneficial bacteria in it with so much sponge. Well the first thing I noticed in the clear water and bright light was a strange scum flowing from it (probably protein and other things) and these weird brown bubbles that came off that I assume were full of dust (they don’t pop and I remember having them when I put pool filter sand in my old tank and brown bubbles formed at the surface) , represented in the 4th, 5th, and 6th picture. Will the grime contaminate the nice plants? Because it also is bringing some algae.

[Jungle Fan]

If you are doing regular maintenance, as you mentioned. squeezing the sponge out in old tank water when you do your water changes, and you've got a routine in regards to feeding, fertilization, and light that doesn't produce big algae problems in itself then I wouldn't sweat it. Your sponge should have a good colony of beneficial bacteria established. If you've got surface film you can always do what I do and run a surface skimmer which I clean daily for one thing to avoid clogging, and to spring shrimp that seem to see a ride in the surface skimmer as the biggest thrill of all out of confinement. Once you've got the tank completely cycled you can always add some Nerite snails, unless you don't like them, or their eggs, or otocinclus to help with some of the minor algae that can occur during cycling. Regular maintenance, and daily observation however are key to preventing algae. Oh, and don't get frazzled when a bit of algae occurs, I don't think I've ever seen a tank completely without algae, not even by well known aquascapers unless they are just set up and uncycled; algae happens! Nice looking tank, and you seem to be well on your way.