5' Skimmer Build in Progress

[tinygiants]

Good Stuff coming here.

I will see my stones next week (I hope). I get real busy at work, but we will see what I can get done in the evenings.

Today I am adding my bubble trap pipeing to my overflow. I hope to get my vent valve this week also. Afte the bubble trap I will be able to install the flowmeter on the skimmer inlet.

I will soon have more info evaluate my design progress. The biggest thing is going to be the air bubble size. I hope the fine pore stones are like Mojoreefs. The only finer stones than them are 25 psi of back pressure. If my fine pore do not do it, I may try the home made diffuser mentioned earlier.

Dale

 

[areze]

unless the basswood or KW diffusers are finer than limewood, by alot... you'll still be wanting.

Im coming close to admiting defeat with the air stone CC skimmer. the idea is sound, it has alot of benefits, but as it stands, all of its benefits are outweighed by the limitations of the bubble size. CC should be a very efficient skimmer, but only in terms of energy consumption. because as far as skimming power per liter of air injected, with bubbles this big they just wont even compare.

plus am I missing something or are these whitewater pumps quite loud? Im wrestling with myself if I want to hook this up 24/7 in my bedroom. it drowns out all the rest of the noise from the tank.

 

[piercho]

The Medo AC pumps are similar to the AES whitewater pumps. I personally would not want a Medo in the same room as the display tank. It produces a steady, but loud IMO, humm. But I would not want a 7' skimmer in the display room, either. I put them in the utility room of the old house and plumbed the sump into the utility room.

 

[areze]

worst part is its a bass kind of frequency. it carries real well.

I wish I could plumb it to a utility room, but Im on the 2nd floor, so short of a 30foot drop to the basement and across the house to boot, no utility rooms to be had.

 

[tinygiants]

I knew the whitewater was loud when I bought it. My fishroom is the basement, so noise is not a issue.

As for defeat, I saw the pics from Mojoreefs skimmer. There is a stone that will geive me what I want. Now I just have to find it.

Dale

 

[goby1]

Are you referring to the sweetwater pumps being loud, or the whitewater pumps? IME, the sweetwater pumps are very quiet. I understand that the sweetwater pumps are more efficient at larger backpressure, which would be desireable when using the fine pore diffusers. I'm really curious to see how the fine pore diffusers function. It has been determined that the medium pore diffusers produce babbles that are too large, correct? Prefilters (HEPA?) seem to be needed for diffuser lifetime extension.... Cheers, G1

 

[tinygiants]

Here is the original pipeing.

Here is the bubble trap pipeing.

Where the tubing comes off the top, I will install this valve.

It is an automatic vent valve. It will only vent gas. In the event that it does fail, I will have the discharge routed to the sump.

Dale

 

[tinygiants]

I found the restriction in my recirc loop. It was the nipple that screws into the pump inlet. The nipple threaded so deeply, that it blocked part of the inlet. When I tested the pump with no head I got 250 gph. After I shortened the nipple and beveled the edges, I pegged my flow meter.

 

[tinygiants]

My new air flowmeter just arrived. I may have the skimmer back in tonight. I will have to take it down when the new stones and air pump come back in. But I will know for sure how much air I was not getting into the column.

I am off to HD for a few fittings......

Dale

 

[areze]

<a href=showthread.php?s=&postid=6393708#post6393708 target=_blank>Originally posted</a> by goby1
Are you referring to the sweetwater pumps being loud, or the whitewater pumps? IME, the sweetwater pumps are very quiet. I understand that the sweetwater pumps are more efficient at larger backpressure, which would be desireable when using the fine pore diffusers. I'm really curious to see how the fine pore diffusers function. It has been determined that the medium pore diffusers produce babbles that are too large, correct? Prefilters (HEPA?) seem to be needed for diffuser lifetime extension.... Cheers, G1

I think the fine pore diffusers would require an air blower. they look to have the guts to back it up. they also look to sound like an air compressor, makes me think outside use only.

 

[DrBDC]

What scale is that on? LPM?

 

[tinygiants]

The fine pore stones have a 15" backpressure. In my use I will need 2.5 psi. My cfm will depend on bubble size and rise rate.

DrBDC
It is SCFH. Standard Cubic Feet Per Hour

 

[DrBDC]

Duhh, I guess I can't read! :lol:

 

[smjtkj]

I want to see some pics of this thing in action!

 

[tinygiants]

When the new air pump and stones geet here. I hope to get the flowmeters all plumbed in today. If I get that done I will post pics.

Dale.

 

[jnarowe]

Dale,

Sorry I am late to this thread! I talked to the tech guys at Coralife and explained that I was having trouble picking an air pump. Once I gave them my application specs they recommended to use the Luft pump rather than a piston pump. This kind of went along with the specs in that the Luft pump puts out 7 psi and the piston pumps less than half that. The Luft pump will require more maintainance since the diaphram will wear out, but for the size skimmers we are building, you would get better results with it.

The Luft pump has adjustable air flow which is a plus too. My skimmer will be a combo of snailman, Herbert T Kornfeld designs and I have an interesting way to mount the stones. I got two 3" Hayward bulkheads and I am fitting them with caps that will have an air line tapped into it. On the inside, there will be an off-set 1/2" PVC pipe also capped, and tapped with four elbows to the air stones. I am starting with the lime wood to see how that goes. So it will be 8 stones total.

What this mount does is makes servicing the stones much easier. My aiir chamber will be made out of 3/8" acrylic so I will be able to inspect the stones. If I need to service them, I can just unscrew the cap and pull out the air stone assembly. The entire skimmer will sit in the sump and can remain running while I service stones.

 

[tinygiants]

Jnarowe,
That sounds cool. I need a diagram or a picture in order to graasp the entire concept, but the gist of the bulkhead and stones attached makes sense.

I was able to mathmaticly model the air needs in my skimmer work sheet. My original purchase was based on a few eroneous assmptions. With my current bubble size and rise rate (hope to improve that with new stones), I need .7 cfm @ 2.6 psi. The LT19 is quite capable of this output.

Here is my recirc line and flowmeter installed.

I was able to fix my earlier blockage problems. I will see what kind of flowrate I can get now when I wet test later today.

Dale

 

[jnarowe]

Wow! Hard-core DIY! I am building mine entirely of 3/8" acrylic and it will of course, be rectangular shaped. The air stone chamber will be 18 x 18 x 12h and the water column will be 12 x 12 x 5'h. Water will enter gravity fed from the display through a 1-1/2" flex PVC line, and exit through a 2" gate valve.

I have no idea how to calculate the air flow I will need or even how much water will pass though the skimmer. I may need to run one Luft pump for each air stone manifold, but that is a wait and see deal.

 

[piercho]

Jonathan,
The Tetra Luft is a great pump, but you might want to evaluate how much air you need. From the AES website for a Luft pump:
@ 1 PSI (2.3 ') 0.09 CFM
@ 5 PSI (11 1/2 ') 0.05 CFM
As a comparison, a modest-sized linear piston pump will put out around 1.5 CFM at 5' of injection pressure, or over ten times more air.

So, the Luft does function very well against backpressure, making it a very good pump for some setups. Where it will fall short, for large-bore skimmers, is output volume. You can use multiple Lufts in a bank to get the amount of air you need, though. This is what Snailman was doing some years ago. As I recall he liked parallel Lufts, compared to a single Medo, because he found the bubble height in the skimmer neck was easier to control.

 

[tinygiants]

Jnarowe,

In a week when I prove my mathmatical predictions, I can update my calculator to handle a square body skimmer. The biggest variable that I can not predict is bubble size and its rise rate in static water. Once I have that info, if the bubble is slow enough, I think I can predict the counter current effect on the bubble. (I have a formula to do it, I just havee to see if it works). Currently with my bubble size, the bubble is so fast that the slow flow in my skimmer has negligible effect (<.5 second difference with and without flow). In any case, if you can get a accurate dwell time of the bubble, I can figure out the CFM needed to maintain 13%.

Dale