View Full Version : gate valve mod question


glxtrix
05-14-2007, 10:24 AM
alright so quick question, I did this mod lastnight to my octopus nw150, def pretty cool, but I was wondering if you have the outport go below the water line or above? I have it slightly above and its making all kinds of noise, even out of the standpipe and its pretty annoying....any thoughts? Thanks.

Lee

mufret
05-14-2007, 10:42 AM
It should be above the water line. If you have it submerged it will cause some back pressure that may effect the skimmer. A couple of things to quiet the skimmer are: having the return run through a filter sock and capping off the top part of the standpipe and drilling a hole in the cap.

MattTVI
05-14-2007, 10:42 AM
Lee,

I put a 90d elbow on the output and some pvc in it to get the outflow below the water line. I don't see any problems w/ it so far.

hth,

Matt

MattTVI
05-14-2007, 10:43 AM
It should be above the water line. If you have it submerged it will cause some back pressure that may effect the skimmer. A couple of things to quiet the skimmer are: having the return run through a filter sock and capping off the top part of the standpipe and drilling a hole in the cap.


wow, good to know... :) thanks mike.

glxtrix
05-14-2007, 10:47 AM
:doh: totally forgot about that cap on top....thanks mike. So this filter sock, will anything do really or are we looking for a specific type?

MattTVI
05-14-2007, 10:52 AM
:doh: totally forgot about that cap on top....thanks mike. So this filter sock, will anything do really or are we looking for a specific type?

If you decide to use the filter sock, clean it regularly, every day or every other day, the detruis build up w/ eventually make it a nitrate generator over time.

Cameron
05-14-2007, 10:53 AM
Contrary to Mikes suggestion partly anyway, what I did was use an elbow on the out of the skimmer into a gate valve. From the gate valve I did a T. The top of the T has a cap with a couple holes drilled in it. The down part of the T of mine does go below the water line, but I drilled holes around the pipe right at the water line as well as below. Works like a champ and noise is very minimal. I hear the pump over the skimmer and no gurgle from air escaping the pipe either.

Some consider it a better setup T before the valve as Mike stated this eliminates more back pressure during times when the skimmer is performing better or worse than expected, but IMO the concept of a gate valve is to create a fine tuned pressure and back the water column up. Once you get it dialed in, it will perform well either way. I am currently using a NW150 till my new skimmer comes in.

MattTVI
05-14-2007, 10:55 AM
I have a question. Besides controlling the water level in the skimmer, what other, if any, adverse effects would that back pressure cause?

Cameron
05-14-2007, 11:01 AM
From my understanding it is when the skimmer is performing better or worse than expected. If the flow from the gate isn't free flowing, you can create unexpected back pressure. Normally this won't happen in the exit pipe after the gate valve if you have a method of purging air and/or run a large part of the plumbing above the water line. You just don't want to back the water up to the gate valve from the sump side or your cup could runneth over.

MattTVI
05-14-2007, 11:04 AM
From my understanding it is when the skimmer is performing better or worse than expected. If the flow from the gate isn't free flowing, you can create unexpected back pressure. Normally this won't happen in the exit pipe after the gate valve if you have a method of purging air and/or run a large part of the plumbing above the water line. You just don't want to back the water up to the gate valve from the sump side or your cup could runneth over.

hmmm, i've been having some problems w/ build up inside my venturi on the intake of my ER5-2. Could that be from the back pressure of my submerged gate valve return?

Cameron
05-14-2007, 11:15 AM
I would bet it is probably either creep or calcium deposits. Have you been running on the high side of calcium lately?

MattTVI
05-14-2007, 11:18 AM
I would bet it is probably either creep or calcium deposits. Have you been running on the high side of calcium lately?

I was using Kent Marine salt for a while, and that was mixing up at a pretty high Calc level, I've tried to get Ca down to 400ppm. I'm not sure how accurate my test kit (aqua pharm) is. It is measuring out to about 400ppm now (havent' checked in a month or so), but I do notice percipitate (is that the right word) when I dose the KH (baking soda) of Randy's 2part recipe.

thanks cam for the info!

glxtrix
05-14-2007, 11:18 AM
FYI, this is exactly how mine is setup.

http://www.marinesolutionsinc.com/catalog/images/OctopusGateValveKitL.jpg

Cameron
05-14-2007, 11:25 AM
I bet you are having calcium deposits on your venturi as it is pretty common. Check and make sure your air intake is well protected from splash and such. I saw someones line clogged with salt because of this problem. How often are you having this problem?

glxtrix I would just drop the pipe into the water about an inch and drill a few holes right at the water level. It is amazing how much quieter it will sound and I have seen zero ill effects from running this way. With the extra holes, water has a higher exit surface area so backing up is virtually impossible unless the sumps water level changes.

MattTVI
05-14-2007, 11:31 AM
I bet you are having calcium deposits on your venturi as it is pretty common. Check and make sure your air intake is well protected from splash and such. I saw someones line clogged with salt because of this problem. How often are you having this problem?


Hey Cam,

I was suspicious of salt splash as well, so I bought a 3/8 hose from HD and installed that on the venturi so that I could have the air intake on the skimmer well away from the water surface. Eye-ball measuring showed about the same level of air volume inside the skimmer's chamber and production was the same.

The problem comes around every couple of weeks it seems like. I occasionally run some RO/DI water throught the venturi line to "clean" it. I started doing this after the first few times the intake clogged up. The clogging takes place in the venturi's nipple (right word?) and if left long enough moves into the area were the hose meets the nipple.

thanks,

Matt

Cameron
05-14-2007, 11:34 AM
Is it a white powerdery/slimy substance or a hard chalky substance?

Soak it in distilled vinegar next time this happens if you can. Otherwise, microwave up some RO water and hook it up so it is sucked in and cleared out.

MattTVI
05-14-2007, 11:44 AM
Def. a hard substance. It's white, crystal like.

mufret
05-14-2007, 12:06 PM
As Cameron stated, the drilled cap will benefit whichever way you have your return configured. I wasn't advocating one way over the other and just made the assumption that there was a tee somewhere in the configuration to vent the return. There are a great number of things that can influence the effective operations of a skimmer and either of the ways suggested should work. Each skimmer, however, has their own "personality" so the same skimmer or other skimmers from the same manufacturer may "act" a little different. Some experimentation is always advisable!

mufret
05-14-2007, 12:27 PM
:doh: totally forgot about that cap on top....thanks mike. So this filter sock, will anything do really or are we looking for a specific type?


A number of different things can be used. A filter bag is another and it won't tend to catch as much stuff. Anything that's used, however, will need to be cleaned periodically. The idea is to disperse the water coming out of the return which will, hopefully, cause less splashing and noise.

glxtrix
05-14-2007, 12:40 PM
ah yes very nice, thanks again mike I'll try those additions and see how it sounds afterwards. Thanks.