new filter

After considering lots of options I went really old-school. A canister seemed overkill for a twenty gallon that's going to house a paradise fish (they like gentle current) and a few bottom-dwellers. Plus I forgot to make a gap into the back of the tank stand and don't want to drill a hole in it. I don't want an HOB for this tank- nor another internal filter than hangs off the rim. What I pictured in mind was something like the sponge filter in my betta tank, but larger and to hold more media options.

So I got this box filter. It's very simple. You layer it with media- Water is pulled in through slots near the base then routed top to bottom, before going out the uplift tube. On the left there are the media I tested it with- on the right templates I cut out of cardboard to fit media inside. I did have to discard some of the sponge and filter pad (rings are just for scale)- because of cutting down to fit-

but added the gravel, bio-cubes and medium/fine sponge. So although I expect a bit of mini-cycle, I hope I have replaced the discarded media with enough volume of new to equal out- so I'm not loosing any bio-capacity. To test it out I put it in a bin with some old tank water and a few gallons of dirty water out of that silly pond container on my deck. I could see the dirty particles getting drawn into the floss. It worked better at picking up debris when I put it on the little foot pedestal and added a second air pump to increase flow. Overnight it got pretty clear and the floss in the filter was definitely dirty.

I put in coarse sponge, marineland cut-to-fit filter pad and fine floss out of the old filter, in that order. Between the corase sponge and marineland media a piece of medium/fine sponge. Then some gravel out of the tank and a layer of porous bio-cubes. I thought the gravel in the base was just for ballast, but found out it's actually to house the bacteria after the water has been mechanically cleaned by all the sponges and stuff.

It feels risky to do this- I can't go back after cutting up that media, unless I sew it together again with fishing line. I ran an airstone on the tank for some circulation so the fishes wouldn't stress too much and I could take my time cutting the media pieces to size. I wanted it to fit snug without much room for bypass, and if I do it right can just rinse these sponges in tank water and re-use forever. (Only the fine floss will need replacing when it starts to fall apart).

My tank looks more sleek now. The noise is very minimal. I've never really liked bubbles in an aquarium- I don't run airstones unless I have to- but it's in the corner so not too noticeable, and it is very - classic in a way. It is visible from the side- later I might obscure it with plants, right now it's nice to be able to glance and check on it.

 I've been watching the tank all day. After an hour the fine debris started to clear out of the water column, and just as I expected, I could see the cories kicking up stuff where it had settled as they moved about, so I think that will help the filter pick up more. Any dead zones I can clean out with siphon during weekly maintenance. The tank is still a bit hazy- but I expect it will take a day or two to bounce back- and it is looking more clear now than a few hours ago. I watch the fishes especially for indication.

Cories look great. They are flirting about, the largest (I'm starting to think a female) wiggling its fins at the others as if excited. They are all poking around and darting between decor and plants when I walk close. Have good color and none are breathing hard or going to the surface repeatedly. Fabio drifts around. He definitely has an easier time swimming in this gentle current. Whether he will last long, I don't know.

I am concerned maybe I got a size too small? This one it said on the website "for up to 45 gallon aquariums" and I thought great, that's twice what I need. It wasn't until I had it up and running that found the small print on the box: it turns over 45 gallons per hour. I know there's different opinions on this, but most aquariums should have turnover rate four or five times the volume of the aquarium, if not more. Granted, I don't have huge waste-producing fish, but... the water is still cloudy. My cories look happy, Fabio looks terrible. I tested halfway through the day: ammonia less than 0.25 (barely tint of green), zero nitrite, 30 nitrates. I think that's okay. I'm going to keep a close eye on it and do water changes if needed (although it is nice the hornwort quit shedding so many needles when I stopped dong the daily wc for the fry).