Conversion..... Hmmmm, perhaps this should be posted under the religious section......

This year I decided to convert my 150 gallon Rubbermaid stock tank into a biofilter for our 2300 gallon pond. Previously the stock tank has been used as a combo-settling chamber for fish solids and a veggie filter. The veggie filter (water hyacinths) coupled with many plants in the pond used to do a pretty good job of keeping my water clear. “Used to”…. Raccoons have been a major problem recently dumping many of my potted plants into the pond and eating most of the water hyacinths. That, coupled with a neighbor giving me a bunch of his goldfish, has resulted in lack of water clarity all last summer and winter. I don’t want crystal clear water but it would be nice to see the fish again…… Here’s my conversion of the stock tank into a skippy biofilter…..

Below is the floor of the stock tank. The drain on the side was about ½” above the bottom. The remaining black stinky fish solids would have to be vacuumed out whenever I drained it. It was a pain. I poured a mix of concrete and raised the bottom so that it now drains pretty well and only takes some spray from the hose to clean out any remaining stuff.


The black ABS is a venturi that our son made for me several years ago. The venturi aerates water entering the pond. I thought surely the backpressure from expelling water near the bottom of the stock tank would force water out the hole in the venturi but it doesn’t. I will leave it up to an engineer or physicist to explain…..


I painted the concrete to seal it and make it smoother. The white pvc cap on top of the venture acts as a muffler. The venturi makes a noticeable gurgling sound as it draws in air into the water and the cap muffles that sound. On the bottom of the stock tank I placed the black ABS saddle shown in the following photo. The discharge pipe will rest on top of the saddle to hold it up several inches from the bottom and also help support the weight of the discharge lines.




Below is the discharge piping in place to make a gentle swirl action.


Below shows the added grating that will support the biofilter media.


Gene at Koi Village suggested I use Savio Springflo as my biofilter media. This media is ¼” wide ribbon-like material with ripples in the ribbon. To contain the media I used tree bird netting that I cut to the appropriate size and then I used zip-lock ties to “sew” the edges together to make pillow-like containers to hold the media. I made two of these, one for each side and stuffed them with the Springflo media.




On top of the biofilter media I placed egg-grate lighting grids to hold the material down.


Green water? What green water? I put bricks on top of the egg-grating to hold them down. You are supposed to put more media such as commercial floor scrubbers on top to add additional filtration and biofilter action but I have chosen to see how what I have works first….. Baby steps…..

Looks good Mikey, how long before the bacteria begin to grow or did you add some?

That looks pretty much like mine. EXCEPT, Pete plumbed into the tank near the bottom and we have a stainless steel spillway at the top that we got from Gene. It's made specifically for 100-150 gallon Rubbermaid tubs. Also, Cindi bought her grid from them. It is much heavier than the grid you and I used and already cut to shape. I put one grid near the bottom on the second ridge then layers of floor scrubber pads, and then another grid. I find them much easier to handle and clean as we have to shut ours down every fall and clean the whole thing. Pete added in a bottom drain last year for easier cleaning. Although it wasn't so bad with the shop vac. I guess I don't understand the use or need of the venturi.

Bullfrog: From what I understand it takes a couple of weeks for the microbes to kick in and make a difference. I didn't add anything to jump start it.

Esther: Water going into my biofilter comes from the bottom drain in the pond. Water on the bottom is supposedly less oxygenated. The venturi oxygenates the water which helps the microbes on the biofilter media.

Bullfrog, Mikey doesn't need anything to jump start it because he is using this on an existing pond. The little critters are already in the water and will quickly set up shop in the media.

OK Mikey, we don't have a bottom drain on the pond. Our pump sits in a laundry tub/skimmer inside the liner so pulls from the surface.

Looks like a very nice setup Mikey and you made it all yourself. I wish I was handy like that and I don't think my DH wants to get involved with the pond.............it's all my baby pretty much but he did make me a waterfall container made out of stainless steel for me and it works great Can't one buy one of these setups already made that you all make somewhere? I suppose if they did they cost alot of bucks I think I will show him these pics of how to do it and see what his reaction is

Janice, mine is pretty much the same as Mikey's. Just water comes from the skimmer at the other end of the pond into the bottom of the tank just like Mikey's. Pete put the two exits facing away just like Mikey did. Oh and I don't have the venturi either. We have the cleanout valve on the back of the long side and the spillway at the top on the other side. Here's the grids and the PVC frame that goes inside ours. You don't want to see our Skippy now. We just shut off the pump and never took out the stuff or cleaned it. The stainless steel spillway has a piece of slate covering it.

It looks really good and I just showed it to DH and he says we don't have a place to put it where it would fit in right w/ the pond. No place to create another water spill in area so I will just keep on pulling up my filter w/ the rope thingy till I get too old to pull it out and clean it all. Perhaps we will be in a warmer state by then and retired with a new pond and better set up plan..........that is if he ever gets back to work again before we are too old and gray

Yah, that can be a problem. We just squeaked ours between the pond and some rose bushes and a tree.

Looks like a very nice setup Mikey and you made it all yourself.

How does that song go....."had a little help from my friends". All I did was copy someone else's ideas/plans.....
http://www.skippysstuff.com/biofiltr.htm

Me too Mikey. Skippy is dead. Did you know?

Are you pulling my leg Esther? The only real Skippy I know of is the peanut butter.....

No Mikey. Skippy is the guy who came up with the idea to use the Rubbermaid tank. He lived in Detroit. I'm gonna look at the Skippy site and see if it tells.

Mikey, I emailed the Skippy website. I am wrong in a way. Skippy is a 7' frog that was their "mascot" for a while. But one of the owners who documented using a Rubbermaid container for a biofilter and put the instructions on their website was one of the owners who passed away a few years ago.

Seven foot frog.........