Plenum Round 2, Ideas Please

I need some ideas for a plenum build for a 65g and 75g.

My friend is giving me his 65g tank stocked with South American cichlids. I got him into the hobby last year and his family caught the MTS earlier. Their new tank is going where the 65g is currently, so I am inheriting it.

My plan is to move my community fish from our 75 gallon into the 65g, and put the S.A.'s in the 75g.

After I set up the 65g, I'll have time to set up a plenum, then set one up in the 75 gallon after transferring the fish out of it and cleaning it out to prep for the S.A.'s.

I found Marineland bio- balls on sale and ordered enough so I can have a layer on the bottom to create the void space needed.

I've got an idea of how I want to finish it off, but I wanted some ideas and suggestions on how the plenum build should go.

Thanks

 

I really wish Novak hadn't used bio-balls in that video. He did it just because he already had them and wasn't using them for anything else. They're only there to support the top of the plenum. If you don't already have them, they're an unnecessary expense.

I've suggested using very short sections of PCV pipe standing on end. A bit more labor cutting the PVC, but the pipe itself is very cheap in standard household sizes. A 10' piece of 3/4" PVC pipe should be under $5. Cut into 1" segments you'd have 120 sq. in. of coverage, though you could spread them out and double or triple the coverage and still have more than adequate support.

An alternative, and one that presents a more uniform solution, is to use egg crate diffraction grating used for light covers. They used to sell heavy duty stuff that was very sturdy. What I see in the stores today is very light weight junk that's almost impossible to even get to the checkout without breaking it. If you can find the heavier stuff of old, it makes a very good top for the plenum. Use the trimmings to make legs. Cut it so the trimming has fingers on one side. Put PVC glue on the fingers and slide them into place on the top. Around the edges and a few places in the middle should be adequate to provide support.

Cover it with polyester window screening. Use an old iron to melt the screening onto the egg crate along the edges. This is what I did years ago to make a UGF plate for my 55 gallon.

 

Very interested, following!

I just might attempt something like this too. I use just plain soil, but sometimes I add gravel at the bottom of a pot (for ex), do you think I'm creating something similar?

Gonna read up on it thanks!

 

So I am returning the Marineland bio-balls.

I was at Home Depot today to get some various materials for our water heater replacement that I hope to tackle on Sunday.

I picked up an extra section of PVC, to create the plenum. Will prob go back and get the light diffuser as well.

I've gotten delayed on building the cabinet for the tank, so I never starter with the plenum.

Already have the new tank, and I divided my buddy's fish into a spare 20 gallon tank and a 50 gallon plastic watering trough for animals. The fish are doing good on our back covered deck for now, until I can get their tank up and running.

I'll post some pics as I start then plenum.

But now I'm not sure if I want to still build the plenum, or now possibly a reverse flow UGF hooked up to the discharge of a canister. .....

angelcraze, you had mentioned you were interested on the subject of plenums and were going to read up on them.

Basically, the plenum is a void space between the bottom glass and the substrate, with the plates of an UGF or other flat perforated surface dividing the two areas and allowing water to slowing pass in and out.

This plenum space is supposed to facilitate an anoxic region of 0.5ppm - 2.0ppm of oxygen in the water.

Since there is still a small amount of O2 left, purely anaerobic bacteria will not thrive there, but something called facultative anaerobic heterotrophic bacteria will. From what I gather, this bacteria can take oxygen from NO3 and PO3 (Nitrate and Phosphate). This reduction of nitrates and phosphates is what interests me.

I started learning about it after CoralBandit made a reference about Dr. Kevin Novak, plenums and anoxic filtration.

A Google search of those terms months ago led me down this rabbit hole......

 

Did you check out what kind of light diffuser they had at Home Depot when you were there? I bought my most recent piece from Menard's. It's borderline junk. I had to pull at least a dozen pieces from the shelf to find one that wasn't already broken. It's fragile stuff that I don't think would work well for a plenum. The one I bought years ago was about a half inch thick and was made from much sturdier plastic. I don't know that I could have walked on it, but it was pretty close. This stuff I got more recently would break to a million pieces before I got even half my weight on it. (I used it to make a holder for art pens so strength wasn't a key factor.)

I found a place online that looks like they have the heavier stuff I bought ages ago, but it also appears they sell only in case quantities. You probably don't want ten of them unless you plan to go into business building plenums. It does give some hope you might be able to find a good quality one locally.

 

I will have to go check out the lighting diffuser tomorrow. Thanks for the tip of how some diffusers can be fragile. I wouldn't have thought to inspect them for being brittle.

If Home Depot's selection is of poor quality, I'll wait until next week to check out some industrial/commercial supply places that will probably stock it. There are 2-3 places that may have it close to where I work in the industrial part of town.

We have no Menards here, but I've always heard about them.

 

Home Depot doesn't list any of the type you'd want online. I've never looked for them in store there. The one I used for my UGF was purchased decades ago, probably at a place that no longer exists.

The one I bought at Menard's is about 1/4" thick and the plastic is pretty thin. With just my fingers it feels like I can get a bit of twist in one of the cells in the middle. I suspect if I really tried I could break it with just thumb and forefinger. It's strong enough for what it was designed for, but nowhere near strong enough for a plenum.

The one I found online was listed as 1/2"x1/2"x1/2", which I took to mean the size of each cell, 1/2"x1/2" and 1/2" thick. That's more like the one I bought years ago.

The local Menard's is huge. Almost too big if you're going in for just one thing. If you include the building materials yard I'd guess it's double the size of the typical Home Depot. Quite a hike if what you need is in the back of the store.

 

Menards sounds awesome!

 

angelcraze, you had mentioned you were interested on the subject of plenums and were going to read up on them.

Basically, the plenum is a void space between the bottom glass and the substrate, with the plates of an UGF or other flat perforated surface dividing the two areas and allowing water to slowing pass in and out.

This plenum space is supposed to facilitate an anoxic region of 0.5ppm - 2.0ppm of oxygen in the water.

Since there is still a small amount of O2 left, purely anaerobic bacteria will not thrive there, but something called facultative anaerobic heterotrophic bacteria will. From what I gather, this bacteria can take oxygen from NO3 and PO3 (Nitrate and Phosphate). This reduction of nitrates and phosphates is what interests me.

I started learning about it after CoralBandit made a reference about Dr. Kevin Novak, plenums and anoxic filtration.

A Google search of those terms months ago led me down this rabbit hole......

Thanks that's the understanding I got too. Like a safer anaerobic bacteria to work with. Anoxic. I don't think it would support sulfur, or at least would limit the amount of it being produced. I don't have sulfur anymore in my deep dirt bed since the plant roots have established themselves, but that took a long time with 8" dirt beds!

 

sorry for asking but these Plenums are good for planted tanks or any kind of tank?
I have read a little bit about that after I saw this thread and I use undergravel filters on my bigger tanks and they work wonders. Of course in addition to power filters as well. or UI get the power filters to power the undergravel filter,

 

trujo777 , Look at Dr. Kevin Novak's channel on YouTube. His planted tanks have plenums and he advises they do great.

I need to update this thread. I will later in the month with pics of the 65g.

 

Just wondering how this plenum turned out?