Undergravel filtration and Cory group fish

[TwoTankAmin]

I had a pre-filter sponge on my powerhead. So, during weekly maint. I needed to rinse it out. It was a PITA to get the foam off of the power head so I would often lift the whole thing off the top of the tube and then detach the foam to rinse it. This left the uplift tube open at the top. In addition, sometimes the power head would not easily come out of the uplift tube and I would end up pulling the tube out of the plate.

Between the opening at the top and the occasional opening into the plate, the two species managed to get down and under the plate. The whole set-up was somewhat jury rigged to accept the powerhead going into the top of the uplift tube.

But, as far as I am concerned a properly set up UGF or RUGF are great bio-filter media. I used to run a hang on with it when I ran it as an RUGF. The upward flow through the gravel prevented a lot of what would otherwise settle into the substrate instead to stay in the water. The hang on was set up for mechanical filtration and pretty much kept the water clean by removing the solid waste. I almost never had to vacuum that tank when I had that set up on it.

 

[Colin_T]

The above brings up a situation with my soon to be new tank build. I will be replacing a 20 gallon cube with a 21 gallon high. I've been waiting for being able to get fresh water scud cultures which just haven't been locally available this year. This could actually be a good thing as I'll be using UG filtration involving a couple of small power heads on 2 risers and another 2 air driven. Since I'll be using medium sized river pebbles as the substrate the scuds could easily establish colonies under the filter plates. It dawned on me that the power heads could pull scuds into the impellers which could disable their function. Since the scuds are so small they could possibly just pass through the impellers but seems to me that they could be an issue.

I don't think you need 2 powerheads and 2 airstones on an undergravel filter in a 20 gallon tank. To me that is overkill on an enormous scale. Especially if you plan on keeping slow moving crustaceans in the tank. I would run one or two airstones and leave it at that.

 

[jaylach]

I don't think you need 2 powerheads and 2 airstones on an undergravel filter in a 20 gallon tank. To me that is overkill on an enormous scale. Especially if you plan on keeping slow moving crustaceans in the tank. I would run one or two airstones and leave it at that.

The main fish would be Panda Garra and they like fast water. The power heads will not run full flow.

 

[GaryE]

Next, I do not agree with this. It is not a universal statement.
Have a look at the pictures on Planetcatfish of Hopisoma sp. (Cw111). You will see that the males get a rather long dorsal fin as adults. Below is one of the pics from there.

Long fins are well known in nature, as long finned fish. Longfins as a noun are a hobby creation, especially if you read the thread and realize at that point we were talking about Hoplisoma paleatum, which in nature has short fins. One of the fish I am considering for a UG filter has a high dorsal - Hoplisoma loretoensis. Check it out on Planet Catfish - it's pretty.
Misreads feed misunderstandings. The way everyone writes on the internet, a space that matters grammatically is easy to miss.

In that 21 gallon, I agree that it's too much, even with small powerheads. Amazon has some small and weak pumps, and they might be good, but I use air or single small powerheads in my 20s, with an HOB as well for current loving fish. I'm one for supposedly overfiltering tanks, and like my plan Bs. Also, it's so much easier to cycle an HOB in advance to buy time for the UG to get up to speed. You can always remove the HOB later if you change the set up for slow water fish.

Years ago I bought three homemade tanks second hand, and they came with homemade UG filters made out of pvc pipe. I used them, and the tanks were very stable (back in my test kit days) and allowed me to breed fish like Satanoperca - delicate ones. There was no plate, but a repeatedly partially cut set of pipes. These are what I've made as my fish crafting project. So I won't have creatures living under the plates. But it happens a lot with commercial ones - I had banjo cats move in under one and only come out every 6 months or so.

Fry in sumps, fry in UGs - I've even found young fish alive in Aquaclears.

I think we should bring back the undergravel filter. We still have the tools invented to keep them working, as standard gear (gravel vacuums), so we'd be all set. They worked in many applications. It's not like the father fish foolishness as an idea once sensibly rejected brought back - they aren't a thought experiment. It's an old tool that works. Nail guns work for some jobs, but hammers are good for others.

 

[Magnum Man]

I've also had critters living under plates... last for me was dwarf mexican cray's , and no filters are safe from critters moving in I repeatedly pull out small hillstream loaches from my hang on back filters, that go up the waterfall... at least with sponge filters there are no moving parts...

if something is living under your plate, it just becomes part of your living filter... I guess it could become a problem, if it's a baby that continues to grow, beyond the space available...

I have about a dozen of what I consider the best made plates, from the 80's just before they fell from grace... I would be running more of them if it weren't for the tubes becoming brittle, and me not being able to easily find replacements... maybe in retirement I'll have more time to search out the small parts for my plates... I had them in all my tanks, before I got out of them 30-40 years ago...

 

[GaryE]

It was the brittleness of the plastic that did in the commercial ones I had. They didn't last many years if exposed to air. And so, I make them.

 

[Colin_T]

I have about a dozen of what I consider the best made plates, from the 80's just before they fell from grace... I would be running more of them if it weren't for the tubes becoming brittle, and me not being able to easily find replacements... maybe in retirement I'll have more time to search out the small parts for my plates... I had them in all my tanks, before I got out of them 30-40 years ago...

We replaced broken uplift tubes with pvc pipe. You just cut a piece to go over the old broken uplift or replace the broken uplift with the pvc pipe. You can glue them to the filter plates or if you want to go extreme, get a fitting for the pvc pipe and glue the fitting over the hole, then put the pvc pipe in the fitting.

 

[jaylach]

In that 21 gallon, I agree that it's too much, even with small powerheads. Amazon has some small and weak pumps, and they might be good, but I use air or single small powerheads in my 20s, with an HOB as well for current loving fish. I'm one for supposedly overfiltering tanks, and like my plan Bs. Also, it's so much easier to cycle an HOB in advance to buy time for the UG to get up to speed. You can always remove the HOB later if you change the set up for slow water fish.

I'll stay with both power heads. They each can pull 127 GPH but I'll throttle them down to around 50 GPH to get my target of 5-6 water turnovers per hour.