DIY Skimmer

[Geoff]

yep, that looks good in general, you got the idea!!

i would move the venturi as close to the pump outlet as possible. this increases the contact time with the bubbles in the water column and it also allows more pressure on the venturi from the pump. it will make smaller bubbles.

as for the outlet. i would put an expansion coupler on the outlet. this will allow you to adjust the height of the water in the skimmer. i find the expansion couplers the easiest way to adjust the water height if ou do not have gate valve on the outlet. since gate valves are tough to find locally, the expansion coupler is it. in the pics on my site the expansion couplers are those barrel looking PVC pipe fittings.

the red pipe going up is a siphon break you do not want the outlet of the skimmer to become a siphon.

G~

[danp_canucks]

Geoff, thank you so much for all your help. I have two questions to ask you.

First I will have the mag 7s outside of the sump. I will do this because I heard that they generate heat, and I cannot have my tank heat up anymore than it already is from the lights. The first diagram shows how the Mag 7 will feed the skimmer. Can you please tell me if this is a viable option, or I will lose too much pressure from the extra piping by putting the pump outside the sump.

Second, on the return, I plan to do the same thing (keep the pump outside of the sump). The question that I have here is should I have the return just dump water into the display tank, or would it make sense to build a simple spray bar, like in the diagram.

Thank You

[Geoff]

i do not like spray bars at the top of the tank. they are very usefull down low near the SB or the BB. up near the top they limit the amount of flow that could be used for keeping the surface clean. spraybars work great for CLS's where keeping siphon back to a minimum is not a concern.

G~

[danp_canucks]

Geoff thank you.

I've completed the skimmer and the plumbing, the problem that I have now, is with the venturi. I made a DIY venturi like outlined in http://thereeftank.com/forums/showthread.php?t=49491. Only I used a 1/2" T with a threaded cap, drilled the cap, and inserted 1/4" tubing like shown in the diagram. The problem that I'm having is as follows: If I place the venturi near the inlet like in Figure 1 and Figure 2, the pump stops sucking in water. If I place the venturi after the outlet of the pump, like in Figure 3 and Figure 4, I am getting water in the air line. Please Help!!!!! I have no idea what could be going wrong

[Geoff]

that type of venturi has to be used immediately before the pump. the air line will need to extended enough to reach out of the water to pull in air. that type of venturi will also not work on an externally mounted pump that is not plumbed below water level. the air inlet for the venturi is acting like a siphon break for your over the sump inlet.

about the only place that that DIY venturi may work is if it is plumbed directly to the outlet of the pump. there might be enough velocity out of the pump to pull air into the tube.

get yourself the Kent 1/2" venturi valve. it will make your life a lot easier.

G~

[danp_canucks]

Geoff Thank You again

This is pretty much what I figured, so I went ahead and ordered one (Venturi Valve). I'll let you know how it works once it arrives. Thank You for all your help.

[Geoff]

keep us posted.

G~

[danp_canucks]

Geoff

Thank you very much for helping all the way through this project. There is absolutely no way that I could have done it without your help and guidance. Although I probably did not save much money by going the DIY route, it was a wonderfull experience, and I have learned a great deal about how a skimmer works, and tank plumbing in general. I could post a pic, but it looks exactly like your skimmer, and I won't be adding anything by adding a picture. Currently I'm trying to calibrate skimmer (it could take a while) right now it's running really wet. Also I've made the collection cup 5" tall.

A quick question: I've made the pvc pipe that goes through the bottom of the collection cup (inside the cup) about 2" longer (taller) then yours, as I thought I would need to compensate for the increase in height of the collection cup. Does this mean that I need to increase the height of the water in my skimmer also by 2"?

[Geoff]

yep, you will need to increase the water height in the skimmer to compensate for the extra height in the collection cup. not a big deal with the size pump you are working with. with more powerfull pumps the smaller the collection cup uptube the harder it is to tune the skimmer.

glad it was a fun project to do. the first skimmer you DIY it is a real close call on whether or not it is cheaper. the skimmers after that are better and cheaper to make, plus you get to play around with different designs once you understand what exactly is going on in a skimmer.

G~

[stephenlchristopher]

how bout a bunch of airstones weighted with a rock and a funnel above leading to a hose that hangs over the sump and leads down into a garbage bag. what's that, 25 bucks?

yes, I am planning on trying this embarassing thing at some point