air skimmer for 300g setup

[tommyp]

Skimmer Update:

I glued 3/8" acrylic to the top and bottom of the pvc tube with weldon 16. The top got a hole routed in it to fit to the 6" riser It also was drilled and tapped for 3/8" nylon bolts. I am hoping that it will seal well enough with a little teflon tape on the threads.

I went through like 4 manifold designs and ended up with one like dons. Just pointing the 4 stones straight up. I know it is not ideal but it was the only thing I could come up with in a hurry. I figure I can make another, once I wrap my head around trying to get them horizontal. 1/2" pvc is almost free.

I drilled the pvc for a unisealed 1 1/2" drain. It is drilled on center about 4" off the bottom with an 90 pointed towards the bottom putting it about 3" off or so. Hartford loop off the other side. I have one of those sliding pvc couplings on it to adjust the water height abit.

A 1" uniseal takes care of the input. which will be run off of the tank drain. it is about 3" from the top of the pvc tube with a 45 to swirl the water and keep it from going directly into the area under the riser tube.

A 1/2" uniseal about the same distance from the top feeds the air to the manifold and to the air pump. I am using 1/2" hard line and speedfit connectors.

I think I might be able to fire this bad thing up tomorrow night. I have to get the return plumbing on my new tank done and fill the skimmer with the 20 gallons of saltwater it will take.

 

[tommyp]

I fired it up today. So far nothing. It just acts like it is boiling the water. I will let it break in more. But I think it is way too turbulent to get good foam. I tried bleeding air off. it makes it less turbulent but it doesn't make anymore foam. Iam hoping it just needs to break in more and is not a more serious issue.

 

[big t]

I think that if you have it so that it is not too turbulant and give it a week you will be a happy boy. It may even take up to 2 weeks to truly break in and for you to get it fine tuned. Good job!

 

[tommyp]

Cool,

I am going to let it run for a while. It was weird when I was filling the skimmer and the air was on it skimmed up some stuff on top but then when put the riser on it and raised the water level it just kinda got crazy. I'll give it some time. It has been a crazy week of fish stuff.

 

[mojoreef]

Tommy here is the plan on how to make sure you get enough air in the skimmer and not to much. Turn off the air pump and measure the height of just the water level in the skimmer chamber. now measure how much higher the water will need to go up if the water was increased 20%. then make a mark. Now increase you air input so it brings the water level up to that mark.
On your skimmer the water level after air is injected should be right at the transistion between the main body and the neck.

Mike

 

[tommyp]

Mike,

I don't think I can get 20% with this air pump. I have the water level set like 3" under the transition and with the air on full it makes it to the transition. I don't know if this is a weak pump or what. I wonder if I lower the stones more that the water will be less turbulent. Part of me says that I need a stronger pump the other says that it will just be more turbulent and not alllow any foam to form. I am going to try to lower the stones and see what that does.

 

[tommyp]

The more I look at the skimmer. I think I have one stone that is letting out a lot more air out then the other three. I am going to pull it and plug the hole and see if that helps. i think that is what is causing the turbulence.

 

[mojoreef]

Hmmm if you cant get 20% you shouldnt be to turbulant. On my skimmer I can make it really turbulant but I have to greatly exceed 20%..?? Also it doesnt have to be 20% it an be somewhere between 15 and 20.


let me know



MIke

 

[tommyp]

Its weird. When I crank up the air there is no way a bubble is staying on the surface of the water. The air rushing to the surface just tosses the bubbles all over the place and they aren't really able to foam. when I bleed off alot of air. the bubbles stay longer but there is not enough air to push the bubles up the tube.

I messed with taking out a stone or two to try to reduce the turbulence but it didn't help.

I am still messing with it. It might just be that there is something on the tube that is kepping the bubbles from foaming and just needs to be broke in. I am trying a bunch of things but basically just letting it run right now.

 

[tommyp]

I just checked the air. The hartford loop is keeping the level constant. So I capped it and shut the air off. Then turned it on full blast. It brought the water level in the tube 2" at the most higher. I don't know if this pump is doing the job? 2" out of 36 isn't 20%. It is the same one that don used so i thought that it would be okay. Maybe I need a bigger air pump. I just set it to be at the top of the riser and am letting it go now.

 

[mojoreef]

Best to let it break in for now before going to any alturnatives. Sounds like your just not getting any surface tension on the bubbles yet (which is a break in thing). Give it some time and see how it fairs.


Mike

 

[tommyp]

Definately. I messed a bit with the stones today but put everything back as I had it. It seems like the way I have it set now that it should skim. I don't know what changed but it is less turbulent now and it is trying to make foam a little. I do think its a break-in thing. The only thing I might do is make a new manifold, the one I have now is kinda tall to have the stones sit above the return. But I think I could make it sit below the return and still not have too many bubbles go out the exit. basically exactly like dons manifold. That should give me another 6-8" of contact time.

 

[rufio173]

How large are these bubbles? The larger the bubbles, the more turbulent and the less likely it is to form a solid foam head.

Also, I have to ask... is this running w/ freshwater, fresh saltwater or actually on your tank ?

Peace,
John H.

 

[rufio173]

Anybody Out there?

 

[tommyp]

weird, never got notification of your first post.

It is just breaking in. The bubbles are about an inch up the neck now. It is on my tank but there is a lot of newly mixed saltwater 150gals + 90gals old water that it is skimming. ( not freshwater I always love that on RC when people test their skimmer in fw and wonder why it doesn't make bubbles.)

I think there is something on the inside of the pvc that was keeping the bubbles from forming. I have a feeling that acrylic skimmers are quicker to break in. The fact that the bubbles weren't forming was making it more turbulent. The skimmer is making more white foam today and I am sure it will make more tomorrow. I think bigt hit it right on the head that it will take a week to get it broken in right. I was concerned initially because DonW's skimmer broke in right away and this one didn't. thought I did something wrong. I shutter to think about the money and juice this thing would need if I had to run it at as a quad beckett or even with a few sedra 9000s. Not that I couldn't afford it just that it seems excessive. I could see a lot of people go airstone instead of beckett.

 

[tommyp]

Foam is about 3" up the neck this morning. Slowly but surely it is breaking in.

 

[tommyp]

Skimmer is breaking in nicely now!

a few hours later

 

[tommyp]

Mojo,

Thanks for all the help and inspiration on this project. It is truely an unbelieveable skimmer that you have come up with.

Tom

 

[mojoreef]

Tommy I would crank that water level up brother! It is better to have more of a mixing chamber then it is to have a longer neck. In the mixing chamber is where all the chemical and mechanical stripping and exchanging goes on. I would have the water level to at least half way up the riser tube


Mike

 

[tommyp]

will do! I will probably have to make a new collection cup too. the riser connection joint is a little leaky so I don't know how high i can put it with out losing some water. But that is no biggie.