A cheap PVC skimmer

[Greenlight2001]

He also said that he added a lid to his skimmer cup b/c the skimmate was drying out and not really coming out the the water, so I added a lid to mine as well. The result? Nice, thick foam this morning. I will snap pictures of what it looks like tonite.

 

 

Happen to have those pictures?

[Mr. Fosi]

Happen to have those pictures?

 

I'm out of town right now (yes, I am checking my posts while out of town).

 

I'll snap them when I get home on Monday.

[Greenlight2001]

I'm out of town right now (yes, I am checking my posts while out of town).

 

I'll snap them when I get home on Monday.

 

 

Cool. Thanks.

[Mr. Fosi]

When I did a water change a couple days ago (before I left town) I intentionally sucked out a bunch of the sand from my 5.5g. Once most of the sand had settled in the bucket, the water still looked like vanilla milk, so I decided to decant the water into the rock bucket and see what the skimmer would pull out.

 

The resulting skimmate blew the cd jewel case off the collection cup, so I weighted it with a roll of duct tape. Within an hour the water had 90% cleared and there was a brown sludge under the foam in the collection cup. I wish I had my camera...

 

I left it to run over the weekend while I was out of town and when I came back, there wasn't much more skimmate in the cup, and there was no foam, but the water level hadn't changed. So, I shut the pump off and wiped out the neck with a succession of three paper towels. When I was done, the paper towels looked like someone had wiped their butt with them and the skimmer was producing a light foam again.

 

When I got home last night, I took a sample of my water to Petsmart for some tests (NH3, NO2, NO3) and it came back with only NO3. Since it appears that the die-off is over and all NH3 has been metabolized, I am going to put the rock in my 5.5 tonight.

 

No pics yet (I am still at work), I will post them after I get home at 5PM.

[Mr. Fosi]

So, here are the pics.

 

I got home to see this lack of skimming power in my collection cup.

 

 

 

So, I shut off the pump, pulled the cup/neck off, and gave them a good scrubbing with dish soap. After I rinsed them really well and reinstalled them, I had this in about 30 sec.

 

 

 

Here is a view of the rocks as of today (day 12) with the cycle complete.

 

 

 

I am going to let it run overnight and see what I get.

 

My wife and I have a sonogram appointment early tomorow and if she catches me taking pictures of my 'fishtank', she'll kill me.

[Mr. Fosi]

I haven't moved the rocks into my tank yet. The fates have conspired against me the last few days, but I really want to get them in tonight if I can. A friend of my wife and I wants to hang out tonight, so maybe I'll get to do it and maybe I won't.

 

I have noticed some reduced skimming in the last few days.

 

There really hasn't been much foam in the cup and I am not seeing as much poo-colored deposits on the neck/cup area.

 

I was concerned that my skimmer had some hidden design flaw that had made it stop functioning, but then I added some topoff water this morning. I added the topoff, b/c just like a tank, the water evaporates out and salinity creeps up.

 

When I added the topoff water I kicked some sediment (like on the top of the powerhead in the above picture) off the bottom and a thick foam was almost immediatly produced. I haven't been turkey basting these last few days b/c my pregnant wife yells at me every time I leave her to go do something with my tanks, but I am going to have to get back on it.

 

I guess this skimmer has enough flow and bubbles to skim out all dissolved organics in such a small volume of water.

[dga]

check out the light fixture precariously laying on top of the 5 gallon bucket.

[Mr. Fosi]

My wife is, as I type, asleep in the bedroom.

 

She is sleeping the sleep that only a cranky pregnant woman can.

 

So I finally got a chance to do a water change and move the rock to my tank.

http://www.nano-reef.com/forums/index.php?...pic=76186&st=40

 

I started by sucking a bunch of the sand out of my tank, then I tried to put the new rock in.

 

 

 

 

There just wasn't enough room in the tank for me to have all the rock (15lbs?) in there and have it look good, so I swapped some of the older crappy (hair and cyano infested) pieces into my rock curing bucket along with the milky sand water (without the sand).

 

 

 

 

This is a picture of the skimmate about 5 min after I dumped the sand water in. Compare this photo with the one (earlier in the thread) that I took just after I scrubbed the cup clean.

 

 

 

 

As you can see, it is some nasty stuff. We'll see how clear the bucket water is as well as what the collection cup holds tomorrow.

[Mr. Fosi]

After my I posted the pictures last night, I played a little Halo. I had to empty the collection cup twice (once in the middle of the game) before I went to bed. This is a picture of the second load before I drained it out.

 

 

 

 

This morning, before I basted the rocks, the water looked like this:

 

 

 

 

You can see that some of the detritus settled out, but this is what I saw in the collection cup before I drained it yet again (I've gotta just buckle down and get that drain plug drilled):

 

 

 

 

After having conducted these tests, I am confidant that it will function just fine on my 5.5g as well as much larger (55g?) SW tanks.

 

My only concern is that I will only need to run it for short periods of time when I put it on my 5.5g. I think that if I let it run 24/7 that it will skim out 99% of the dissolved organics, but that last 1% won't be enough to foam into the cup and will just deposit on the neck where it will decompose, thereby negating some of the skimmer's benefit.

 

This poses a problem because wooden airstones need to be run constantly or they will plug up. I would not have to worry about either of those concerns if the skimmer were venturi driven.

 

So, right now I am looking for input of people with solid skimmer experience to answer these questions:

 

(1) Am I correct about the 99%-1% foam deposition problem?

(2) Do you think that running the skimmer intermittently is a good solution?

(3) Assuming the first two questions are answered 'yes', will a flow of ~100gph be enough to run an effective venturi injector?

[neanderthalman]

I believe the wetworx nano-skimmer uses approximately 100gph as a venturi. I could be way wrong though.

[Mr. Fosi]

You are right about that.

 

It took a little digging to find, but his origional (non-recirculating) was a small 80-100gph hagen powerhead. He apparantly used that sort of pump for both the asperating (which is what I want to do) and the injection style.

 

I've been thinking about what pump I am going to use to feed the skimmer. I can stick with the little minijet 110gph that I am using now or I could move up to a marineland0-550 145gph...

 

If I step up to larger input, I may have to replumb the skimmer outlet from 1/2" to 3/4", but that wouldn't be a big deal.

 

If I do modify this skimmer to be an asperating venturi rather than airstone driven, I will need to add a drop-tube to the input in the skimmer body to get the bubbles to the bottom. That will also be easy since I jam-fitted the 3/4" elbow.

 

 

[neanderthalman]

I'm planning to build a skimmer as well, using an MJ400 I have kicking around. This design seems quite a bit simpler to construct than the wetworx nano-skimmer that I was planning to build, so I'd like to see what you can come up with.

[Mr. Fosi]

This design seems quite a bit simpler to construct than the wetworx nano-skimmer that I was planning to build...

 

That is the main reason that I designed this.

 

Given the close tolerances required, I simply do not have the tools or patience to make a wetworx skimmer that will function well and not leak.

[Mr. Fosi]

I think I am going to setup a 10g AGA to house my rejected/curing LR.

 

The whole 5g bucket thing has completely taken over my home office and I don't like it. It is a huge mess and it looks like a science project. While I don't mind the science project look, my wife hates it and I would like it to be more tidy and managable.

 

I am going to move the rock to the 10g and I will probably put my magnum 350 canister on it for circulation. I think I may put a little more light over the tank as well so I can encourage the macro growth on my newest piece of LR.

 

While I am doing all this, I think I am going to break the skimmer down and clean it.

 

I am going to start testing asperating venturis on my various powerheads and pumps tonight and I may even be able to finish the conversion tonight if I can come up with something that works.

 

I am also going to start thinking about a bracket that will allow the skimmer to hang-on if I wish.

 

This whole thing is sure to freak my wife out, "YOU SAID YOU WEREN'T GOING TO DO A 10 GALLON UNTIL AFTER WE'VE MOVED!" It is going to be fun trying to explain why having another tank running isn't really like having another tank running, "Honey, I can just take all this rock and throw it in a 5g bucket with a lid when it is time to move. After all, we've already spent the $$ on the rock, wouldn't it be a waste to let it die?"

 

Wish me luck.

[Mr. Fosi]

So here we are.

 

I haven't had a chance to mess around with venturi mods on my minijet, but I did get my rock moved into that 10g. Suprisingly, my wife didn't bat an eye.

 

 

 

 

Here's the drop tube and a closeup of the end. The open end will face away from the outlet.

 

 

 

 

The inside of the skimmer inlet before and after I added the tube.

 

 

 

 

And shot of the whole thing sans the pump. It looks a little crooked b/c the top isn't firmly fitted on top.

 

[neanderthalman]

I'm not so sure about having the inlet so close to the outlet. You might wind up with a lot of microbubbles making it out of the skimmer. Have you considered putting a riser tube on the outlet? That might keep microbubbles out.

[Mr. Fosi]

Have you considered putting a riser tube on the outlet?

 

I don't get it... Can you draw a picture of what you are talking about?

 

BTW, the 110gph pump cranks out a good amount of small bubbles when I stick an airhose w/a valve in the intake.

[neanderthalman]

To be entirely honest, I dont really know if it would help all that much.......

 

[Mr. Fosi]

I'm not sure that adding a riser tube would do much either. Plus, it'd be a real PITA b/c the bottom of the skimmer has already been glued on.

 

The inlet drop tube actually terminates about 4" above the outlet.

 

Since the venturi test went well, I am going to try hooking it up today with the newly designed mods.

 

I'll post pics once I have ascertained the success/failure of the new design.

[neanderthalman]

I did some more thinking on it, and I don't think it'll help at all. The idea with the riser tube is to have the linear velocity of the water passing through the pipe be less than the linear velocity of a microbubble trying to reach the surface. In order to be most effective, you'd want the vertical section of pipe before it reaches the outlet to be as large as possible, so as to reduce the linear velocity. You can't get much larger than the entire diameter of the skimmer.

 

The only reason it MAY help is that it could prevent water and bubbles from the inlet from scooting over to the outlet without giving the bubbles a chance to rise. That, of course, may or may not happen.

[Mr. Fosi]

Well, I decided not to do your lift tube b/c I couldn't figure out how to get it in there with the bottom glued on.

 

I have run into several problems with this new venturi design:

 

(1) Bottom neck joint started leaking.

 

Solution: Glue it.

 

 

 

 

(2) What looked like good bubble production in the 100gph test translated to mediocre bubble production compared to the wooden air diffuser. I didn't bother getting a pic of it, but there wasn't the violent effervescing water surface that the diffuser produced, only a light sort of champagne bubbling.

 

Solution: Replace 100gph minijet with 145gph marinland 550 powerhead fitted with intake venturi. Only a partial solution since, using the wooden wooden air diffuser is my benchmark, the 145gph pump only produced about 35% the volume of bubbles as the previous design.

 

 

 

 

(3) Water level climbing higher than the outlet, causing breather tube to erupt into a saltwater gyser.

 

Solution: Limit input w/o switching pumps and resize the breather hole.

 

 

 

 

(4) Bubbles gathering inside intake tube (but don't yet seem to restrict flow).

 

Solution: ??

 

 

 

 

So far, this venturi design is more work than the air diffuser design.

 

I am not impressed with it, but I am going to let it run until I go to bed. If everything looks good when I retire, I will let it go all night and see what is in the cup in the morning.

 

EDIT: Part of the problem is that my intake hose is too long. The bubbles are slowing down and coalescing inside the hose, resulting is a lack of microbubbles inside the skimmer.

[Mr. Fosi]

I took the skimmer offline last night since it wasn't doing jack.

 

The venturi idea would work better if the pump was plumbed externally and fed the skimmer directly (i.e. with no intervening hose/pipe).

 

Since I don't have any well-sealing pumps like a mag, quiet, or mj I am going to keep it as an airstone skimmer.

 

I did, however, find a couple plumbing pieces that I have been looking for. I am going to include them in the plumbing tonight or tomorrow, after which I will post pics.

[Mr. Fosi]

The guy at the LFS was right, Lowes has a much better plumbing section than Home Depot.

 

The promised pics:

 

The compression coupling that allows me to change the pipe height (and therefore the water height in the skimmer) by tightening/loosening nuts. There are rubber collars inside the nuts that fit around the pipe and are squeezed when you tighten the nuts. The two halves of the pipe meet at the center inside the fitting.

 

 

 

 

The non-ball valve that I have been trying to find. Ball valves are hard to fine-tune and are also more expensive than these screw-down types. You will also notice that I added a longer breather tube. The longer tube will allow for a slightly larger head pressure and hopefully less gurgling.

 

 

 

 

A full monty shot with the new mods. Notice the hose clamps on some of the fittings that will have to take pressure w/o leaking. I want to leave as many joints as I can unglued so I have the option of easily adding/subtracting mods as they are suggested or discarded. I will also eventually have to clean the various parts of the skimmer and that will be impossible if they are all glued. I haven't had a chance to test this hose clamp method of sealing possible leak spots, but I will begin a new test tomorrow afternoon.

 

[Mr. Fosi]

Well, for reasons yet unknown, my skimmer keeps trying to overflow.

 

I am using the same 100gph pump that was working before and I tried limiting the input this morning and it still wanted to overflow.

 

I think the problem may be caused by the longer breather tube. If it isn't that, it might be that I inadvertantly elongated the output when I added the compression fitting. If it isn't either of those, then it might be the new valve.

 

I am going to mess around with it tonight, but I may not be able to work on it for long before my wife gets p!$$ed that I am not spending time with her.

[Mr. Fosi]

It was the valve.

 

I played around w/it for about an hour last night; outlet height, breather height, pump volume, and the valve.

 

Once I removed the valve from the outlet, the water height stayed level just like before. I decided to add the valve to the inlet and that was a great idea. Now, instead of having to stick my hand in the tank and mess around with a chincy flow control on the pump, I can just twist a knob on the skimmer.

 

The longer breather tube does cut down slightly on the gurgling sound, but it is just as easy to lightly jam a piece of filter floss in the breather hole.

 

The compression coupling is a wonderful addition. Now, instead of having to shut the skimmer off, drain it down, and swap out the outlet pipe just to manage water height, I can do it by twisting a knob and sliding a pipe. It also eliminates the need for any sort of valve on the outlet, since if you want the water to ride higher, you just lengthen the pipe a little.

 

The slip fitting on the bottom of the collection cup (which is not clamped) has started leaking, so I am going to glue it tonite. None of the other joints have leaked, so I believe that the hoseclamp method of sealing dry-fit joints (including the large diameter fittings on the skimmer body) is worthy of trust.

 

I haven't seen any skimmate in the collection cup, but I am going to blame that on the Magnum350 canister filter that is circulating the ~5g of water in the tank. Since there doesn't appear to be anything to skim in the rock tank, I will probably move the skimmer to my 5.5g AGA display tank tonight.