Oceanic / Venturi question

matlet · 11-13-2005, 02:47 PM

I have been avidly reading about the DIY skimmers since my Oceanic Venturi skimmer is not doing the job. It worked well for several months and then I had to take it apart and clean it more and more often. I now have to take it out of my sump at least weekly. The venturi valve gets clogged with calcified deposits.

Interestingly, many of you mentioned that you must put the venturi valve before the pump, while my Oceanic has it after the pump. Think that might make a difference on the clogging?

Otherwise, I plan on building a DIY.

Thanks,

Mark

yardboy · 11-14-2005, 12:11 PM

My DIY venturi skimmer (see my webpage) is after the pump. I'm not sure it would work before, it would restrict the suction and not pull anything through the pump, I'd think?

Tim224DT · 11-14-2005, 01:13 PM

Mine happens to be before my pump. Check my website also for the design on my venturi. I got the design from Vince(Wharyat). Post some pics of what your skimmer looks like. The only thing i am about to change on my skimmer design is on the outlet pipe that flows back into my sump im going to put a "T" to break the siphone of the water flowing back into the sump.

Tim

matlet · 11-14-2005, 02:03 PM

Thanks to both Tim224DT and Yardboy. My venturi valve is glued to the canister, so it is not removable. In order to try it before my pump, I'd have to just plug the old one and install a new one.

The inside of the nub where my airline hose attaches, gets clogged. I have added new airline hose and ran it 6 feet outside my tank, fearing that I was sucking in salt air that was calcifying on the inside.

Has anyone else had this problem of deposits collecting at the air hose attachment point?

My Oceanic sits inside my sump, so cleaning it often is a royal pain. I'm liking the DIY models I'm seeing more and more. Ease of maintenance is key.

Thanks,

Mark

Geoff · 11-14-2005, 04:24 PM

you are able to get a much greater pressure gradient with a venturi after the pump. when they are before, you have to be carefull not to starve the pump. those with the venturi before the pump have a wider open venturi valve just so this does not happen.

G~

matlet · 11-14-2005, 05:55 PM

Geoff,

Thank you. That makes sense.

Mark

Geoff · 11-15-2005, 02:45 AM

the ones with the venturi before the pump also rely on either the impeller itself to chop up the bubbles more, or they have a special needle wheel impeller to do it.

G~

impur · 11-16-2005, 08:37 PM

I have a Pacific Imports skimmer. It does ok, and uses a rio pump with needlewheel and the venturi before the pump. It sure does produce lots of tiny bubbles! I still need to remove the pump about once a month and clean off the venturi due to salt deposits. Over time they build up and eventually clog the venturi.

RandyStacyE · 12-05-2005, 02:48 PM

It depends on the type of skimmer and the type of pump (venturi before/after). I typically prefer to have the venturi before the pump (chews up the bubbles better) but that will cavitate the pump and not allow it to push anywhere near as much flow.

If you place the venturi after the pump you will get maximum flow, but you have to solely on the venturi to give you the right consistancy of bubbles (number and size). Sure venturis can use a little valve on them to restruct the volume of air, but that can sometimes defeat the purpose in some cases.

I had to up the size of my pump (for a skimmer) because the pump (venturi before) would work quite right. My skimmer was a hang on so it was difficult to push enough air and water through.

Pumps with needle wheels are the best for sure.