Hi - no one mentioned this yet, but if you rinse out any filter floss or pads in regular tap water this will kill all the bacteria in them.
This will prevent the eventual creation of nitrates, which is probably the main problem. You'll have to rinse them more, but overall you don't want muck to stay in the filter floss for long.
The increased flow does this too, keeping detrius suspended, sent to your overflow, & out of your tank. So pointing it towards the overflow from the bottom of the tank is actually best.
I use Matrix from Seachem, which removes nitrates through support of the type of bacteria that processes nitrate, aside from the ammonia & nitrite kind. Purigen (also Seachem) also helps, but isn't bacteria based, but rather absorption based, so it "fills up" but can be recharged.
You can add depth to your sand bed (also supports bacteria that processes nitrates), but in a nano, this generally isn't necessary with Matrix & Purigen. It's also a huge hassle with an established tank.
Phosphates are used by algae extremely quickly, so even if you test low (like .25), this isn't necessarily reflective of true levels & you can still have growth.
The best way to remove Phosphate is to vacuum detrius (debris & waste). I tried this with success, but ultimately didn't have the time to do it every other day. So I tried a phosphate songe.
A ton of phosphate sponges are on the market, but I had great success with just a mesh bag of aragonite sand.
I put it in my overflow to let the water run through it & phosphates bonded to the calcium carbonate. Eventually the sand will "fill up" with phosphate. I change it out every couple of months, since my 30 gallon didn't need too much.
Hope my experiences help you.
