My New System

[POC3442]

For the fish tank the highest the water level would be from the ground is 29 inches.

[POC3442]

I feel rediculous posting again...but are there any grow medias other than hydroton that does the same thing and is cheaper? Like would Rockwool Granulate or Coirblock or Perlite work?


P.S. If there is a way for me to edit a post I posted more than 10 minutes ago please let me know because it seem that after 10 minutes or so you can not edit the post you just posted.

[svc]

gravel...

[POC3442]

gravel...

I am running 1/4-1/2" gravel...but Gary said coarser...so not sure how big...but I was thinking that either the swirl filter or the moving bed bio-filter was going to need more surface area or whatnot to allow room for the bacteria to change ammonium to nitrite to nitrate.

[svc]

If cost is a concern i think gravel is the closest to hydroton you will find. I think with that beautiful gravel bed already set up I would use it as is for the grow bed.
Add some solid's removal so it doesn't get built up in the first place. Separate biofilter will help you get your N to nitrate.

[GaryD]

Hi POC,

I totally understand the concept...but what I don't understand is how is the water going to go from the fish tank into the swirl filter and then into my moving bed bio-filter(not sure what that is...just fancy term for 200 litre drum filled with expanded clay?) if the fish tank is sitting on the ground.

The water in the fish tank.......and the two filter barrels.....is at the same height. When you add water to the fish tank (from the pump located in the second barrel), an equal amount of water is displaced......you are simply recirculating the water through the entire system.

The moving bed bio-filter (in your situation) would be a 200 litre barrel containing about 60 litres of suitable media......probably something like Kaldnes K1. That would cost you around $150.

Since I'm using 1/4" gravel you'd sugest me going to 1/2" gravel? I would love to go to clay pebbles(I assume you mean Hydroton) but it is just so expensive. Grow bed can hold 51 gallons @ $30 for 10 gallons of it...would equate to $150 just for the Hydroton without shipping.

If you're going to use gravel, I'd rather see you go to 3/4".

It was my understanding that as long as you had enough surface area to allow the bacteria to switch amonia to nitrite to nitrate the nitrate levels did not matter. What happens to these levels if you do not do a water change...and do you know why? Just curious.

Your nitrate levels will continue to rise. High nitrate levels, in the right circumstances, can lead to a nitrite spike. In any case, you don't have sufficient surface area in your grow bed to support 200lbs of fish.

P.S. On a side note it really suck that all the pictures were messed up when these new forums got placed because most of these devices like DaveOponic swirl tank is explained through pictures apparently LOL!

I agree.....but, it wasn't something that we could foreshadow......and there's nothing we can do about it now.

If you put a swirl tank & filter arrangement in place......and you change the size of the gravel.....you can run your system as it is. You just won't have sufficient nitrification to enable you to carry the amount of fish that you suggested earlier.

Gary

[POC3442]

The water in the fish tank.......and the two filter barrels.....is at the same height. When you add water to the fish tank (from the pump located in the second barrel), an equal amount of water is displaced......you are simply recirculating the water through the entire system.

LOL It's so simple I feel like an idiot for not understanding the concept!

The moving bed bio-filter (in your situation) would be a 200 litre barrel containing about 60 litres of suitable media......probably something like Kaldnes K1. That would cost you around $150.

I'm assuming these 55 Gallon Plastic Barrels will suffice? Also, do you think 50 liters of K1 would suffice as well since it seems to come in 25 and 50L bags? Or would I be better off getting 75L insted? I know it has to move so i don't want to have too much in there. "Litres of K1 media will handle up to 250 grammes of food per day." Btw a 2-2.5 lb tilapia eats how many grams of food per day?

If you're going to use gravel, I'd rather see you go to 3/4".

I'll see what I can do...around here it was very hard to find gravel that would not be super sharp and or change the pH of the water. Most of it has a ton of limestone rock in it.

Your nitrate levels will continue to rise. High nitrate levels, in the right circumstances, can lead to a nitrite spike. In any case, you don't have sufficient surface area in your grow bed to support 200lbs of fish.

I'm confused why the surface area of the grow bed matters. Unless it's because larger grow bed=more plants=less nitrate levels. Do you think in the future I would be safe adding another 3x4 foot grow bed to the same system?

If you put a swirl tank & filter arrangement in place......and you change the size of the gravel.....you can run your system as it is.

Just get me the diagrams or put me in the right direction...I found this Vortex Directions online. It's my understanding that the Vortex barrel will have to be off the ground a little bit to allow yourself to drain the solids out of the bottom of the barrel.


On a side note...is it sad I look forward to your post each day? I feel like I'm a stalker or something.

[GaryD]

Hi POC,

LOL It's so simple I feel like an idiot for not understanding the concept!

Don't be concerned.....there are a bewildering array of possible AP permutations.

I'm assuming these 55 Gallon Plastic Barrels will suffice? Also, do you think 50 liters of K1 would suffice as well since it seems to come in 25 and 50L bags? Or would I be better off getting 75L insted? I know it has to move so i don't want to have too much in there. "Litres of K1 media will handle up to 250 grammes of food per day." Btw a 2-2.5 lb tilapia eats how many grams of food per day?

The barrels would be better if they came with lids.....but you can cut the top out of those without lids.

I'll see what I can do...around here it was very hard to find gravel that would not be super sharp and or change the pH of the water. Most of it has a ton of limestone rock in it.

Can you source river pebbles? They're much smoother.

I'm confused why the surface area of the grow bed matters. Unless it's because larger grow bed=more plants=less nitrate levels. Do you think in the future I would be safe adding another 3x4 foot grow bed to the same system?

Sorry sloppy wording on my part. What I should have spoken about was the surface area of the media in your grow bed. The bigger the grow bed, the more media it can contain.....and the greater the total surface area of the media.....upon which the bacteria can grow.

Just get me the diagrams or put me in the right direction...I found this Vortex Directions online. It's my understanding that the Vortex barrel will have to be off the ground a little bit to allow yourself to drain the solids out of the bottom of the barrel.

That's essentially what DaveOponic's filter looks like.....minus the laundry basket and filter foam. You need only raise the barrel far enough off the floor to attach a 90 degree bend to the bulkhead fitting (or Uni-Seal) in the bottom.

On a side note...is it sad I look forward to your post each day? I feel like I'm a stalker or something.

We all started in the same place. Throughout the years, I've been fortunate to have received sound advice and assistance from others......and I see it as my responsibility to reciprocate. If, however, you find yourself being overwhelmed by the sadness, feel free to send me a fat cheque.

Gary

[POC3442]

Can you source river pebbles? They're much smoother.
Sorry sloppy wording on my part. What I should have spoken about was the surface area of the media in your grow bed. The bigger the grow bed, the more media it can contain.....and the greater the total surface area of the media.....upon which the bacteria can grow.

I'll check on the river pebbles...but what about Coirblock? I only ask because it looks like it would have a ton more surface area than the river pebbles...and at $9 for 2.5 cubic feet if I had to replace what the roots were in would only cost $25. Since 50 gallons is only 6.6 cubic feet.

That's essentially what DaveOponic's filter looks like.....minus the laundry basket and filter foam. You need only raise the barrel far enough off the floor to attach a 90 degree bend to the bulkhead fitting (or Uni-Seal) in the bottom.

Any thoughts how to make the inside bottom of it a cone shape? I was thinking I could maybe add sand or something light to fill a void then put hard plastic over it and seal the inserted plastic to the barrel so that it would make sucking the solids out easier. One thing i read somewhere was that with that type of vortex system if the bottom isn't a cone shape you have to suck it out a couple of times because all of the sediment isn't right by the drain. I was thinking something like this.



Also what PVC pipe sizes do you think?I figured that the smaller the diameter the pipe was coming from the fish tank into the vortex filter the more suction it would have in the fish tank so it would have an easier time picking up solids. Also should make the vortex spin faster?
And what about from the vortex tank to the moving bio filter tank? 1/2-1" would be fine? Does this size matter at all?
The pump to the grow bed? I was thinking 3/4" since that's what I'm currently using.

[GaryD]

Hi POC,

I found the images of DaveOponic's swirl filter.

Photo 1 shows the inside of the barrel with the inlet arrangement in place. In the interests of simplicity I'd dispense with this and use a 90 degree bend......like the one that is in my swirl tank (Photo 2). You can see the dump outlet in the bottom of the blue barrel.
Photo 3 shows the laundry basket in place. It is lined with filter foam and coral is placed in the bottom of the basket.
Photo 4 shows a build up of solids in the base of the barrel.
Photo 5 shows the inside of the laundry basket when the filter is operating.

I'm sure that Dave can explain how this works better than I can.....and he claims that it leaves the water in his fish tank very clear.

Thinking back to his explanation of how he operates the filter, I recall that he said that it goes for prolonged periods between being cleaned. In this respect, it functions as a clarifier rather than a swirl filter.

A swirl filter is designed to allow removal of the solids every few hours if necessary.....before oxygen is lost in their digestion. While mineralising the solids in the system (by using a clarifier) runs contrary to my preferences, it still traps the solids and prevents them from building up in your grow beds.

I'll check on the river pebbles...but what about Coirblock? I only ask because it looks like it would have a ton more surface area than the river pebbles...and at $9 for 2.5 cubic feet if I had to replace what the roots were in would only cost $25. Since 50 gallons is only 6.6 cubic feet.

Coco coir is not generally suitable for flood and drain use and nor is it likely to be useful from a nitrification perspective. Coco Coir is generally watered (for just a few seconds) once or twice per day.....with the flow controlled by a timer. It will also turn your fish tank water the colour of black coffee.

Any thoughts how to make the inside bottom of it a cone shape? I was thinking I could maybe add sand or something light to fill a void then put hard plastic over it and seal the inserted plastic to the barrel so that it would make sucking the solids out easier. One thing i read somewhere was that with that type of vortex system if the bottom isn't a cone shape you have to suck it out a couple of times because all of the sediment isn't right by the drain.

While a cone is the ideal shape for the bottom of a swirl tank, it's not essential. The other possibility is to make the swirl tank small enough (say 20 litres/5 gallons) that, when you want to clean it, you just stir up the entire tank an dump it.

I might try an experiment with a plastic bucket and see how I go.

Also what PVC pipe sizes do you think?I figured that the smaller the diameter the pipe was coming from the fish tank into the vortex filter the more suction it would have in the fish tank so it would have an easier time picking up solids. Also should make the vortex spin faster?
And what about from the vortex tank to the moving bio filter tank? 1/2-1" would be fine? Does this size matter at all?
The pump to the grow bed? I was thinking 3/4" since that's what I'm currently using.

As to pipe sizes, for a small system like yours, you might get away with 3/4" but I'd prefer to see you use one and a half inches throughout. While 3/4" seems quite large initially, you should remember that it will become lined with bio-film after a short time and that will inhibit the flow of water.

Gary